CVE-2021-46981 (GCVE-0-2021-46981)
Vulnerability from cvelistv5
Published
2024-02-28 08:13
Modified
2025-05-04 12:40
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: nbd: Fix NULL pointer in flush_workqueue Open /dev/nbdX first, the config_refs will be 1 and the pointers in nbd_device are still null. Disconnect /dev/nbdX, then reference a null recv_workq. The protection by config_refs in nbd_genl_disconnect is useless. [ 656.366194] BUG: kernel NULL pointer dereference, address: 0000000000000020 [ 656.368943] #PF: supervisor write access in kernel mode [ 656.369844] #PF: error_code(0x0002) - not-present page [ 656.370717] PGD 10cc87067 P4D 10cc87067 PUD 1074b4067 PMD 0 [ 656.371693] Oops: 0002 [#1] SMP [ 656.372242] CPU: 5 PID: 7977 Comm: nbd-client Not tainted 5.11.0-rc5-00040-g76c057c84d28 #1 [ 656.373661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 [ 656.375904] RIP: 0010:mutex_lock+0x29/0x60 [ 656.376627] Code: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 <f0> 48 0f b1 55 d [ 656.378934] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246 [ 656.379350] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 656.379915] RDX: ffff888104cf2600 RSI: ffffffffaae8f452 RDI: 0000000000000020 [ 656.380473] RBP: 0000000000000020 R08: 0000000000000000 R09: ffff88813bd6b318 [ 656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40 [ 656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00 [ 656.382166] FS: 00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000 [ 656.382806] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0 [ 656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 656.384927] Call Trace: [ 656.385111] flush_workqueue+0x92/0x6c0 [ 656.385395] nbd_disconnect_and_put+0x81/0xd0 [ 656.385716] nbd_genl_disconnect+0x125/0x2a0 [ 656.386034] genl_family_rcv_msg_doit.isra.0+0x102/0x1b0 [ 656.386422] genl_rcv_msg+0xfc/0x2b0 [ 656.386685] ? nbd_ioctl+0x490/0x490 [ 656.386954] ? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0 [ 656.387354] netlink_rcv_skb+0x62/0x180 [ 656.387638] genl_rcv+0x34/0x60 [ 656.387874] netlink_unicast+0x26d/0x590 [ 656.388162] netlink_sendmsg+0x398/0x6c0 [ 656.388451] ? netlink_rcv_skb+0x180/0x180 [ 656.388750] ____sys_sendmsg+0x1da/0x320 [ 656.389038] ? ____sys_recvmsg+0x130/0x220 [ 656.389334] ___sys_sendmsg+0x8e/0xf0 [ 656.389605] ? ___sys_recvmsg+0xa2/0xf0 [ 656.389889] ? handle_mm_fault+0x1671/0x21d0 [ 656.390201] __sys_sendmsg+0x6d/0xe0 [ 656.390464] __x64_sys_sendmsg+0x23/0x30 [ 656.390751] do_syscall_64+0x45/0x70 [ 656.391017] entry_SYSCALL_64_after_hwframe+0x44/0xa9 To fix it, just add if (nbd->recv_workq) to nbd_disconnect_and_put().
References
Impacted products
Vendor Product Version
Linux Linux Version: e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Version: e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Version: e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Version: e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Version: e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Version: 0b584bf573ae59021069c056c22d65d5721910cb
Version: 9f0f39c92e4f50189155dfb13bb5524372e40eba
Version: 92ec11cccb7fc14331e000ab2337f60aa433433e
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: Fix NULL pointer in flush_workqueue\n\nOpen /dev/nbdX first, the config_refs will be 1 and\nthe pointers in nbd_device are still null. Disconnect\n/dev/nbdX, then reference a null recv_workq. The\nprotection by config_refs in nbd_genl_disconnect is useless.\n\n[  656.366194] BUG: kernel NULL pointer dereference, address: 0000000000000020\n[  656.368943] #PF: supervisor write access in kernel mode\n[  656.369844] #PF: error_code(0x0002) - not-present page\n[  656.370717] PGD 10cc87067 P4D 10cc87067 PUD 1074b4067 PMD 0\n[  656.371693] Oops: 0002 [#1] SMP\n[  656.372242] CPU: 5 PID: 7977 Comm: nbd-client Not tainted 5.11.0-rc5-00040-g76c057c84d28 #1\n[  656.373661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014\n[  656.375904] RIP: 0010:mutex_lock+0x29/0x60\n[  656.376627] Code: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 \u003cf0\u003e 48 0f b1 55 d\n[  656.378934] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246\n[  656.379350] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000\n[  656.379915] RDX: ffff888104cf2600 RSI: ffffffffaae8f452 RDI: 0000000000000020\n[  656.380473] RBP: 0000000000000020 R08: 0000000000000000 R09: ffff88813bd6b318\n[  656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40\n[  656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00\n[  656.382166] FS:  00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000\n[  656.382806] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0\n[  656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n[  656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n[  656.384927] Call Trace:\n[  656.385111]  flush_workqueue+0x92/0x6c0\n[  656.385395]  nbd_disconnect_and_put+0x81/0xd0\n[  656.385716]  nbd_genl_disconnect+0x125/0x2a0\n[  656.386034]  genl_family_rcv_msg_doit.isra.0+0x102/0x1b0\n[  656.386422]  genl_rcv_msg+0xfc/0x2b0\n[  656.386685]  ? nbd_ioctl+0x490/0x490\n[  656.386954]  ? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0\n[  656.387354]  netlink_rcv_skb+0x62/0x180\n[  656.387638]  genl_rcv+0x34/0x60\n[  656.387874]  netlink_unicast+0x26d/0x590\n[  656.388162]  netlink_sendmsg+0x398/0x6c0\n[  656.388451]  ? netlink_rcv_skb+0x180/0x180\n[  656.388750]  ____sys_sendmsg+0x1da/0x320\n[  656.389038]  ? ____sys_recvmsg+0x130/0x220\n[  656.389334]  ___sys_sendmsg+0x8e/0xf0\n[  656.389605]  ? ___sys_recvmsg+0xa2/0xf0\n[  656.389889]  ? handle_mm_fault+0x1671/0x21d0\n[  656.390201]  __sys_sendmsg+0x6d/0xe0\n[  656.390464]  __x64_sys_sendmsg+0x23/0x30\n[  656.390751]  do_syscall_64+0x45/0x70\n[  656.391017]  entry_SYSCALL_64_after_hwframe+0x44/0xa9\n\nTo fix it, just add if (nbd-\u003erecv_workq) to nbd_disconnect_and_put()."
        }
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      "providerMetadata": {
        "dateUpdated": "2025-05-04T12:40:42.413Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1c4962df938891af9ab4775f5224ef8601764107"
        },
        {
          "url": "https://git.kernel.org/stable/c/cde4b55cfb24522dcbba80bbdb0c082303e76c43"
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        {
          "url": "https://git.kernel.org/stable/c/b31d237796fd618379ec8e0f4de3370b5e4aeee7"
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        },
        {
          "url": "https://git.kernel.org/stable/c/79ebe9110fa458d58f1fceb078e2068d7ad37390"
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      "title": "nbd: Fix NULL pointer in flush_workqueue",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-46981",
    "datePublished": "2024-02-28T08:13:10.972Z",
    "dateReserved": "2024-02-27T18:42:55.945Z",
    "dateUpdated": "2025-05-04T12:40:42.413Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-46981\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-02-28T09:15:37.320\",\"lastModified\":\"2024-12-06T15:59:55.120\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnbd: Fix NULL pointer in flush_workqueue\\n\\nOpen /dev/nbdX first, the config_refs will be 1 and\\nthe pointers in nbd_device are still null. Disconnect\\n/dev/nbdX, then reference a null recv_workq. The\\nprotection by config_refs in nbd_genl_disconnect is useless.\\n\\n[  656.366194] BUG: kernel NULL pointer dereference, address: 0000000000000020\\n[  656.368943] #PF: supervisor write access in kernel mode\\n[  656.369844] #PF: error_code(0x0002) - not-present page\\n[  656.370717] PGD 10cc87067 P4D 10cc87067 PUD 1074b4067 PMD 0\\n[  656.371693] Oops: 0002 [#1] SMP\\n[  656.372242] CPU: 5 PID: 7977 Comm: nbd-client Not tainted 5.11.0-rc5-00040-g76c057c84d28 #1\\n[  656.373661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014\\n[  656.375904] RIP: 0010:mutex_lock+0x29/0x60\\n[  656.376627] Code: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 \u003cf0\u003e 48 0f b1 55 d\\n[  656.378934] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246\\n[  656.379350] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000\\n[  656.379915] RDX: ffff888104cf2600 RSI: ffffffffaae8f452 RDI: 0000000000000020\\n[  656.380473] RBP: 0000000000000020 R08: 0000000000000000 R09: ffff88813bd6b318\\n[  656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40\\n[  656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00\\n[  656.382166] FS:  00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000\\n[  656.382806] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\\n[  656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0\\n[  656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\\n[  656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\\n[  656.384927] Call Trace:\\n[  656.385111]  flush_workqueue+0x92/0x6c0\\n[  656.385395]  nbd_disconnect_and_put+0x81/0xd0\\n[  656.385716]  nbd_genl_disconnect+0x125/0x2a0\\n[  656.386034]  genl_family_rcv_msg_doit.isra.0+0x102/0x1b0\\n[  656.386422]  genl_rcv_msg+0xfc/0x2b0\\n[  656.386685]  ? nbd_ioctl+0x490/0x490\\n[  656.386954]  ? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0\\n[  656.387354]  netlink_rcv_skb+0x62/0x180\\n[  656.387638]  genl_rcv+0x34/0x60\\n[  656.387874]  netlink_unicast+0x26d/0x590\\n[  656.388162]  netlink_sendmsg+0x398/0x6c0\\n[  656.388451]  ? netlink_rcv_skb+0x180/0x180\\n[  656.388750]  ____sys_sendmsg+0x1da/0x320\\n[  656.389038]  ? ____sys_recvmsg+0x130/0x220\\n[  656.389334]  ___sys_sendmsg+0x8e/0xf0\\n[  656.389605]  ? ___sys_recvmsg+0xa2/0xf0\\n[  656.389889]  ? handle_mm_fault+0x1671/0x21d0\\n[  656.390201]  __sys_sendmsg+0x6d/0xe0\\n[  656.390464]  __x64_sys_sendmsg+0x23/0x30\\n[  656.390751]  do_syscall_64+0x45/0x70\\n[  656.391017]  entry_SYSCALL_64_after_hwframe+0x44/0xa9\\n\\nTo fix it, just add if (nbd-\u003erecv_workq) to nbd_disconnect_and_put().\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: nbd: corrija el puntero NULL en flush_workqueue Abra /dev/nbdX primero, config_refs ser\u00e1 1 y los punteros en nbd_device seguir\u00e1n siendo nulos. Desconecte /dev/nbdX, luego haga referencia a un recv_workq nulo. La protecci\u00f3n de config_refs en nbd_genl_disconnect es in\u00fatil. [656.366194] ERROR: desreferencia del puntero NULL del kernel, direcci\u00f3n: 00000000000000020 [656.368943] #PF: acceso de escritura del supervisor en modo kernel [656.369844] #PF: c\u00f3digo_error(0x0002) - p\u00e1gina no presente [656.370717] PGD 10cc87067 P 4D 10cc87067 PUD 1074b4067 PMD 0 [656.371693] Ups: 0002 [#1] SMP [656.372242] CPU: 5 PID: 7977 Comm: nbd-client No contaminado 5.11.0-rc5-00040-g76c057c84d28 #1 [656.373661] Nombre de hardware: PC est\u00e1ndar QEMU (i 440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 01/04/2014 [ 656.375904] RIP: 0010:mutex_lock+0x29/0x60 [ 656.376627] C\u00f3digo: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00  48 0f b1 55 d [ 656.378934 ] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246 [ 656.379350] RAX: 0000000000000000 RBX: 00000000000000000 RCX: 0000000000000000 [ 656.379915 ] RDX: ffff888104cf2600 RSI: fffffffaae8f452 RDI: 0000000000000020 [ 656.380473] RBP: 00000000000000020 R08: 00000000000000000 R09: ffff88813bd6b31 8 [656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40 [ 656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00 [ 656.3821 66] FS: 00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000 [ 656.382806] CS: 0010 DS: 0000 ES: 0000 CR0 : 0000000080050033 [ 656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0 [ 656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 656.384927] Seguimiento de llamadas : [656.385111] flux_workqueue+0x92 /0x6c0 [ 656.385395] nbd_disconnect_and_put+0x81/0xd0 [ 656.385716] nbd_genl_disconnect+0x125/0x2a0 [ 656.386034] genl_family_rcv_msg_doit.isra.0+0x102/0x1b0 [ 656 .386422] genl_rcv_msg+0xfc/0x2b0 [656.386685]? nbd_ioctl+0x490/0x490 [656.386954]? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0 [ 656.387354] netlink_rcv_skb+0x62/0x180 [ 656.387638] genl_rcv+0x34/0x60 [ 656.387874] netlink_unicast+0x26d/0x590 [ 6 56.388162] netlink_sendmsg+0x398/0x6c0 [656.388451]? netlink_rcv_skb+0x180/0x180 [656.388750] ____sys_sendmsg+0x1da/0x320 [656.389038] ? ____sys_recvmsg+0x130/0x220 [ 656.389334] ___sys_sendmsg+0x8e/0xf0 [ 656.389605] ? ___sys_recvmsg+0xa2/0xf0 [656.389889] ? handle_mm_fault+0x1671/0x21d0 [ 656.390201] __sys_sendmsg+0x6d/0xe0 [ 656.390464] __x64_sys_sendmsg+0x23/0x30 [ 656.390751] do_syscall_64+0x45/0x70 [656.391017] Entry_SYSCALL_64_after_hwframe+0x44/0xa9 Para solucionarlo, simplemente agregue if (nbd-\u0026gt;recv_workq) a nbd_disconnect_and_put().\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-476\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.4\",\"versionEndExcluding\":\"5.4.120\",\"matchCriteriaId\":\"74E02350-43FB-4F4F-B822-E9CA42371263\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.5\",\"versionEndExcluding\":\"5.10.38\",\"matchCriteriaId\":\"2BB4E5E8-4AAD-475A-A1B9-F287254C7D72\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.11\",\"versionEndExcluding\":\"5.11.22\",\"matchCriteriaId\":\"83B53E9A-F426-4C03-9A5F-A931FF79827E\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.12\",\"versionEndExcluding\":\"5.12.5\",\"matchCriteriaId\":\"0274929A-B36C-4F4C-AB22-30A0DD6B995B\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1c4962df938891af9ab4775f5224ef8601764107\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/54b78ba7e96e5fe1edb8054e375d31a6c0dc60dc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/79ebe9110fa458d58f1fceb078e2068d7ad37390\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/b31d237796fd618379ec8e0f4de3370b5e4aeee7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/cde4b55cfb24522dcbba80bbdb0c082303e76c43\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/1c4962df938891af9ab4775f5224ef8601764107\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/54b78ba7e96e5fe1edb8054e375d31a6c0dc60dc\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/79ebe9110fa458d58f1fceb078e2068d7ad37390\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/b31d237796fd618379ec8e0f4de3370b5e4aeee7\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/cde4b55cfb24522dcbba80bbdb0c082303e76c43\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://git.kernel.org/stable/c/1c4962df938891af9ab4775f5224ef8601764107\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/cde4b55cfb24522dcbba80bbdb0c082303e76c43\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/b31d237796fd618379ec8e0f4de3370b5e4aeee7\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/54b78ba7e96e5fe1edb8054e375d31a6c0dc60dc\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/79ebe9110fa458d58f1fceb078e2068d7ad37390\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T05:24:38.514Z\"}}, {\"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-46981\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-02-28T19:55:25.767523Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-05-23T19:01:13.707Z\"}, \"title\": \"CISA ADP Vulnrichment\"}], \"cna\": {\"title\": \"nbd: Fix NULL pointer in flush_workqueue\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"e9e006f5fcf2bab59149cb38a48a4817c1b538b4\", \"lessThan\": \"1c4962df938891af9ab4775f5224ef8601764107\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"e9e006f5fcf2bab59149cb38a48a4817c1b538b4\", \"lessThan\": \"cde4b55cfb24522dcbba80bbdb0c082303e76c43\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"e9e006f5fcf2bab59149cb38a48a4817c1b538b4\", \"lessThan\": \"b31d237796fd618379ec8e0f4de3370b5e4aeee7\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"e9e006f5fcf2bab59149cb38a48a4817c1b538b4\", \"lessThan\": \"54b78ba7e96e5fe1edb8054e375d31a6c0dc60dc\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"e9e006f5fcf2bab59149cb38a48a4817c1b538b4\", \"lessThan\": \"79ebe9110fa458d58f1fceb078e2068d7ad37390\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"0b584bf573ae59021069c056c22d65d5721910cb\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"9f0f39c92e4f50189155dfb13bb5524372e40eba\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"92ec11cccb7fc14331e000ab2337f60aa433433e\", \"versionType\": \"git\"}], \"programFiles\": [\"drivers/block/nbd.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.4\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.4\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.4.120\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.4.*\"}, {\"status\": \"unaffected\", \"version\": \"5.10.38\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.11.22\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.11.*\"}, {\"status\": \"unaffected\", \"version\": \"5.12.5\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.12.*\"}, {\"status\": \"unaffected\", \"version\": \"5.13\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"drivers/block/nbd.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/1c4962df938891af9ab4775f5224ef8601764107\"}, {\"url\": \"https://git.kernel.org/stable/c/cde4b55cfb24522dcbba80bbdb0c082303e76c43\"}, {\"url\": \"https://git.kernel.org/stable/c/b31d237796fd618379ec8e0f4de3370b5e4aeee7\"}, {\"url\": \"https://git.kernel.org/stable/c/54b78ba7e96e5fe1edb8054e375d31a6c0dc60dc\"}, {\"url\": \"https://git.kernel.org/stable/c/79ebe9110fa458d58f1fceb078e2068d7ad37390\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnbd: Fix NULL pointer in flush_workqueue\\n\\nOpen /dev/nbdX first, the config_refs will be 1 and\\nthe pointers in nbd_device are still null. Disconnect\\n/dev/nbdX, then reference a null recv_workq. The\\nprotection by config_refs in nbd_genl_disconnect is useless.\\n\\n[  656.366194] BUG: kernel NULL pointer dereference, address: 0000000000000020\\n[  656.368943] #PF: supervisor write access in kernel mode\\n[  656.369844] #PF: error_code(0x0002) - not-present page\\n[  656.370717] PGD 10cc87067 P4D 10cc87067 PUD 1074b4067 PMD 0\\n[  656.371693] Oops: 0002 [#1] SMP\\n[  656.372242] CPU: 5 PID: 7977 Comm: nbd-client Not tainted 5.11.0-rc5-00040-g76c057c84d28 #1\\n[  656.373661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014\\n[  656.375904] RIP: 0010:mutex_lock+0x29/0x60\\n[  656.376627] Code: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 \u003cf0\u003e 48 0f b1 55 d\\n[  656.378934] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246\\n[  656.379350] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000\\n[  656.379915] RDX: ffff888104cf2600 RSI: ffffffffaae8f452 RDI: 0000000000000020\\n[  656.380473] RBP: 0000000000000020 R08: 0000000000000000 R09: ffff88813bd6b318\\n[  656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40\\n[  656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00\\n[  656.382166] FS:  00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000\\n[  656.382806] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\\n[  656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0\\n[  656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\\n[  656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\\n[  656.384927] Call Trace:\\n[  656.385111]  flush_workqueue+0x92/0x6c0\\n[  656.385395]  nbd_disconnect_and_put+0x81/0xd0\\n[  656.385716]  nbd_genl_disconnect+0x125/0x2a0\\n[  656.386034]  genl_family_rcv_msg_doit.isra.0+0x102/0x1b0\\n[  656.386422]  genl_rcv_msg+0xfc/0x2b0\\n[  656.386685]  ? nbd_ioctl+0x490/0x490\\n[  656.386954]  ? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0\\n[  656.387354]  netlink_rcv_skb+0x62/0x180\\n[  656.387638]  genl_rcv+0x34/0x60\\n[  656.387874]  netlink_unicast+0x26d/0x590\\n[  656.388162]  netlink_sendmsg+0x398/0x6c0\\n[  656.388451]  ? netlink_rcv_skb+0x180/0x180\\n[  656.388750]  ____sys_sendmsg+0x1da/0x320\\n[  656.389038]  ? ____sys_recvmsg+0x130/0x220\\n[  656.389334]  ___sys_sendmsg+0x8e/0xf0\\n[  656.389605]  ? ___sys_recvmsg+0xa2/0xf0\\n[  656.389889]  ? handle_mm_fault+0x1671/0x21d0\\n[  656.390201]  __sys_sendmsg+0x6d/0xe0\\n[  656.390464]  __x64_sys_sendmsg+0x23/0x30\\n[  656.390751]  do_syscall_64+0x45/0x70\\n[  656.391017]  entry_SYSCALL_64_after_hwframe+0x44/0xa9\\n\\nTo fix it, just add if (nbd-\u003erecv_workq) to nbd_disconnect_and_put().\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.4.120\", \"versionStartIncluding\": \"5.4\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.38\", \"versionStartIncluding\": \"5.4\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.11.22\", \"versionStartIncluding\": \"5.4\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.12.5\", \"versionStartIncluding\": \"5.4\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.13\", \"versionStartIncluding\": \"5.4\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"4.14.149\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"4.19.79\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"5.3.6\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-05-04T12:40:42.413Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-46981\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2025-05-04T12:40:42.413Z\", \"dateReserved\": \"2024-02-27T18:42:55.945Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-02-28T08:13:10.972Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


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Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.