ghsa-2qfv-5w3v-jvfv
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
nbd: don't allow reconnect after disconnect
Following process can cause nbd_config UAF:
1) grab nbd_config temporarily;
2) nbd_genl_disconnect() flush all recv_work() and release the initial reference:
nbd_genl_disconnect nbd_disconnect_and_put nbd_disconnect flush_workqueue(nbd->recv_workq) if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...)) nbd_config_put -> due to step 1), reference is still not zero
3) nbd_genl_reconfigure() queue recv_work() again;
nbd_genl_reconfigure config = nbd_get_config_unlocked(nbd) if (!config) -> succeed if (!test_bit(NBD_RT_BOUND, ...)) -> succeed nbd_reconnect_socket queue_work(nbd->recv_workq, &args->work)
4) step 1) release the reference;
5) Finially, recv_work() will trigger UAF:
recv_work nbd_config_put(nbd) -> nbd_config is freed atomic_dec(&config->recv_threads) -> UAF
Fix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so that nbd_genl_reconfigure() will fail.
{
"affected": [],
"aliases": [
"CVE-2025-21731"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-27T02:15:16Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: don\u0027t allow reconnect after disconnect\n\nFollowing process can cause nbd_config UAF:\n\n1) grab nbd_config temporarily;\n\n2) nbd_genl_disconnect() flush all recv_work() and release the\ninitial reference:\n\n nbd_genl_disconnect\n nbd_disconnect_and_put\n nbd_disconnect\n flush_workqueue(nbd-\u003erecv_workq)\n if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...))\n nbd_config_put\n -\u003e due to step 1), reference is still not zero\n\n3) nbd_genl_reconfigure() queue recv_work() again;\n\n nbd_genl_reconfigure\n config = nbd_get_config_unlocked(nbd)\n if (!config)\n -\u003e succeed\n if (!test_bit(NBD_RT_BOUND, ...))\n -\u003e succeed\n nbd_reconnect_socket\n queue_work(nbd-\u003erecv_workq, \u0026args-\u003ework)\n\n4) step 1) release the reference;\n\n5) Finially, recv_work() will trigger UAF:\n\n recv_work\n nbd_config_put(nbd)\n -\u003e nbd_config is freed\n atomic_dec(\u0026config-\u003erecv_threads)\n -\u003e UAF\n\nFix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so\nthat nbd_genl_reconfigure() will fail.",
"id": "GHSA-2qfv-5w3v-jvfv",
"modified": "2025-03-13T15:32:49Z",
"published": "2025-02-27T03:34:02Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21731"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6bef6222a3f6c7adb6396f77f25a3579d821b09a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/844b8cdc681612ff24df62cdefddeab5772fadf1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9793bd5ae4bdbdb2dde401a3cab94a6bfd05e302"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a8ee6ecde2b7bfb58c8a3afe8a9d2b848f580739"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d208d2c52b652913b5eefc8ca434b0d6b757f68f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e3be8862d73cac833e0fb7602636c19c6cb94b11"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e70a578487a47d7cf058904141e586684d1c3381"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e7343fa33751cb07c1c56b666bf37cfca357130e"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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- Confirmed: The vulnerability is confirmed from an analyst perspective.
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- 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.