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KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernel

Type: advisorySource: Official CVE List1 source record

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.

Announced Group revision 1
Original source ↗

CVE-2025-21779

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2025-21779

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "214ff83d4473a7757fa18a64dc7efe3b0e158486",
        "lessThan": "61224533f2b61e252b03e214195d27d64b22989a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "214ff83d4473a7757fa18a64dc7efe3b0e158486",
        "lessThan": "45fa526b0f5a34492ed0536c3cdf88b78380e4de",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "214ff83d4473a7757fa18a64dc7efe3b0e158486",
        "lessThan": "5393cf22312418262679eaadb130d608c75fe690",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "214ff83d4473a7757fa18a64dc7efe3b0e158486",
        "lessThan": "874ff13c73c45ecb38cb82191e8c1d523f0dc81b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "214ff83d4473a7757fa18a64dc7efe3b0e158486",
        "lessThan": "aca8be4403fb90db7adaf63830e27ebe787a76e8",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "214ff83d4473a7757fa18a64dc7efe3b0e158486",
        "lessThan": "ca29f58ca374c40a0e69c5306fc5c940a0069074",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "214ff83d4473a7757fa18a64dc7efe3b0e158486",
        "lessThan": "a8de7f100bb5989d9c3627d3a223ee1c863f3b69",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "arch/x86/kvm/hyperv.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.20"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.20",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.236",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.179",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.129",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.79",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.16",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.13.4",
        "versionType": "semver",
        "lessThanOrEqual": "6.13.*"
      },
      {
        "status": "unaffected",
        "version": "6.14",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "arch/x86/kvm/hyperv.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2025-21779

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#26942 · Revision 1
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Publisher date
Read the original announcement

Revision history

  1. CVE-2025-21779 · Revision 1Source updated