ghsa-mmj4-6ppp-mqr2
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernel
Advertise support for Hyper-V's SEND_IPI and SEND_IPI_EX hypercalls if and only if the local API is emulated/virtualized by KVM, and explicitly reject said hypercalls if the local APIC is emulated in userspace, i.e. don't rely on userspace to opt-in to KVM_CAP_HYPERV_ENFORCE_CPUID.
Rejecting SEND_IPI and SEND_IPI_EX fixes a NULL-pointer dereference if Hyper-V enlightenments are exposed to the guest without an in-kernel local APIC:
dump_stack+0xbe/0xfd __kasan_report.cold+0x34/0x84 kasan_report+0x3a/0x50 __apic_accept_irq+0x3a/0x5c0 kvm_hv_send_ipi.isra.0+0x34e/0x820 kvm_hv_hypercall+0x8d9/0x9d0 kvm_emulate_hypercall+0x506/0x7e0 __vmx_handle_exit+0x283/0xb60 vmx_handle_exit+0x1d/0xd0 vcpu_enter_guest+0x16b0/0x24c0 vcpu_run+0xc0/0x550 kvm_arch_vcpu_ioctl_run+0x170/0x6d0 kvm_vcpu_ioctl+0x413/0xb20 __se_sys_ioctl+0x111/0x160 do_syscal1_64+0x30/0x40 entry_SYSCALL_64_after_hwframe+0x67/0xd1
Note, checking the sending vCPU is sufficient, as the per-VM irqchip_mode can't be modified after vCPUs are created, i.e. if one vCPU has an in-kernel local APIC, then all vCPUs have an in-kernel local APIC.
{
"affected": [],
"aliases": [
"CVE-2025-21779"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-27T03:15:18Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Reject Hyper-V\u0027s SEND_IPI hypercalls if local APIC isn\u0027t in-kernel\n\nAdvertise support for Hyper-V\u0027s SEND_IPI and SEND_IPI_EX hypercalls if and\nonly if the local API is emulated/virtualized by KVM, and explicitly reject\nsaid hypercalls if the local APIC is emulated in userspace, i.e. don\u0027t rely\non userspace to opt-in to KVM_CAP_HYPERV_ENFORCE_CPUID.\n\nRejecting SEND_IPI and SEND_IPI_EX fixes a NULL-pointer dereference if\nHyper-V enlightenments are exposed to the guest without an in-kernel local\nAPIC:\n\n dump_stack+0xbe/0xfd\n __kasan_report.cold+0x34/0x84\n kasan_report+0x3a/0x50\n __apic_accept_irq+0x3a/0x5c0\n kvm_hv_send_ipi.isra.0+0x34e/0x820\n kvm_hv_hypercall+0x8d9/0x9d0\n kvm_emulate_hypercall+0x506/0x7e0\n __vmx_handle_exit+0x283/0xb60\n vmx_handle_exit+0x1d/0xd0\n vcpu_enter_guest+0x16b0/0x24c0\n vcpu_run+0xc0/0x550\n kvm_arch_vcpu_ioctl_run+0x170/0x6d0\n kvm_vcpu_ioctl+0x413/0xb20\n __se_sys_ioctl+0x111/0x160\n do_syscal1_64+0x30/0x40\n entry_SYSCALL_64_after_hwframe+0x67/0xd1\n\nNote, checking the sending vCPU is sufficient, as the per-VM irqchip_mode\ncan\u0027t be modified after vCPUs are created, i.e. if one vCPU has an\nin-kernel local APIC, then all vCPUs have an in-kernel local APIC.",
"id": "GHSA-mmj4-6ppp-mqr2",
"modified": "2025-04-10T15:31:42Z",
"published": "2025-02-27T03:34:06Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21779"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/45fa526b0f5a34492ed0536c3cdf88b78380e4de"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5393cf22312418262679eaadb130d608c75fe690"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/61224533f2b61e252b03e214195d27d64b22989a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/874ff13c73c45ecb38cb82191e8c1d523f0dc81b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a8de7f100bb5989d9c3627d3a223ee1c863f3b69"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aca8be4403fb90db7adaf63830e27ebe787a76e8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ca29f58ca374c40a0e69c5306fc5c940a0069074"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
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