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TI-2026-52299 Aliases CVE-2026-74516GHSA-p473-wqx8-95rq

KVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active

Priority LOW 37Published · Updated

Key facts

Attack vector
Local
Privileges required
High
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 16 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active Always update x2APIC MSR intercepts for L1 when AVIC is deactivated, even if L2 is active and KVM is using a separate MSR bitmap to run L2. If AVIC is fully enabled prior to running L2, and is then inhibited while L2 is active (for a VM-scoped inhibit), then KVM will run L1 with AVIC disabled, but with x2APIC MSR intercepts disabled, i.e. will allow L1 to read most of the host's APIC state, send arbitrary interrupts, change task priority, and ultimately trivially DoS the host. E.g. sending a self-IPI in L1 on HYPERV_REENLIGHTENMENT_VECTOR, 0xee, with CONFIG_HYPERV=n in the host kernel as a "safe" PoC, yields: Spurious interrupt (vector 0xee) on CPU#425. Acked And hacking KVM to abuse kvm_set_posted_intr_wakeup_handler() to register a handler and WARN on POSTED_INTR_WAKEUP_VECTOR yields: ------------[ cut here ]------------ WARNING: arch/x86/kvm/svm/svm.c:5594 at pi_wakeup_handler+0x9/0x10 [kvm_amd], CPU#156: nested_x2apic_t/316940 CPU: 156 UID: 0 PID: 316940 Comm: nested_x2apic_t Tainted: G S U Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER Hardware name: Google Astoria-Turin/astoria, BIOS 0.20260209.0-0 02/09/2026 RIP: 0010:pi_wakeup_handler+0x9/0x10 [kvm_amd] Call Trace: <IRQ> sysvec_kvm_posted_intr_wakeup_ipi+0x64/0x80 </IRQ> <TASK> asm_sysvec_kvm_posted_intr_wakeup_ipi+0x1a/0x20 RIP: 0010:vcpu_run+0x1430/0x1e40 [kvm] kvm_arch_vcpu_ioctl_run+0x2c1/0x600 [kvm] kvm_vcpu_ioctl+0x580/0x6b0 [kvm] __se_sys_ioctl+0x6d/0xb0 do_syscall_64+0x10a/0x480 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x46ff4b </TASK> ---[ end trace 0000000000000000 ]---

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00135 2nd percentileScored 2026-11-07
Fix Partial Linux (Linux): 6.1.183, 6.6.151, 6.12.103 +3Red Hat: 4 advisoriesRed Hat: 16 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux6.0 and later6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8, 7.2Patch availableCNA
  • Linux VendorLinux Affected 6.0 and later Fixed in 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8, 7.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8, 7.2

Red Hat 4 advisories

  • RHSA-2026:76739 Released 2026-10-08 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.55.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.55.1.el9_8, kernel-64k-devel-5.14.0-687.55.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.55.1.el9_8, kernel-64k-5.14.0-687.55.1.el9_8, kernel-64k-core-5.14.0-687.55.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.55.1.el9_8, libperf-5.14.0-687.55.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.55.1.el9_8, kernel-rt-64k-5.14.0-687.55.1.el9_8, kernel-rt-64k-core-5.14.0-687.55.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.55.1.el9_8, kernel-rt-core-5.14.0-687.55.1.el9_8, kernel-rt-debug-5.14.0-687.55.1.el9_8 +9
  • RHSA-2026:76738 Released 2026-10-08 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • 10Base-SMTV kernel-modules-internal-6.12.0-211.63.1.el10_2
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.63.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.63.1.el10_2, kernel-64k-devel-6.12.0-211.63.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.63.1.el10_2, kernel-64k-6.12.0-211.63.1.el10_2, kernel-64k-core-6.12.0-211.63.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.63.1.el10_2, libperf-6.12.0-211.63.1.el10_2
    • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal-6.12.0-211.63.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.63.1.el10_2, kernel-rt-64k-6.12.0-211.63.1.el10_2, kernel-rt-64k-core-6.12.0-211.63.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.63.1.el10_2, kernel-rt-core-6.12.0-211.63.1.el10_2, kernel-rt-debug-6.12.0-211.63.1.el10_2 +9
  • RHSA-2026:75747 Released 2026-10-05 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.171.1.el8_10, kernel-4.18.0-553.171.1.el8_10, kernel-abi-stablelists-4.18.0-553.171.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.171.1.el8_10
Show 1 more Red Hat advisories
  • RHSA-2026:75746 Released 2026-10-05 · Red Hat rating Important
    kernel-rt security, bug fix, and enhancement update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-core-4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-4.18.0-553.171.1.rt7.512.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-core-4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-4.18.0-553.171.1.rt7.512.el8_10 +7

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 9AffectedNo fix yet
10Base-SMTVFixed RHSA-2026:76738
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:75747
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:75747
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux Hidden (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:75746
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:75746
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:76739
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-74516
  2. 2026-10-03 Alias added: GHSA-p473-wqx8-95rq
  3. 2026-10-05 Fix available: RHSA-2026:75746 · Red Hat
  4. 2026-10-05 Fix available: RHSA-2026:75747 · Red Hat
  5. 2026-10-05 Fix available: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8), Red Hat Enterprise Linux NFV (v. 8) +1 · Red Hat
  6. 2026-10-09 Fix available: RHSA-2026:76739 · Red Hat
  7. 2026-10-09 Fix available: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) +2 · Red Hat
  8. 2026-10-18 CISA SSVC decision points changed
  9. 2026-10-26 Fix available: RHSA-2026:76738 · Red Hat
  10. 2026-10-26 Fix available: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) +4 · Red Hat

References

Other 6

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21727 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences