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TI-2026-33800 Aliases CVE-2026-46076GHSA-gj33-hwgc-v3v8

KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1

Priority LOW 33CWE-863Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
Low · Low · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-863.

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1 Explicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want to intercept VMMCALL, nested_svm_l2_tlb_flush_enabled() is true, and the hypercall is something other than one of the supported Hyper-V hypercalls. When all of the above conditions are met, KVM will intercept VMMCALL but never forward it to L1, i.e. will let L2 make hypercalls as if it were L1. The TLFS says a whole lot of nothing about this scenario, so go with the architectural behavior, which says that VMMCALL #UDs if it's not intercepted. Opportunistically do a 2-for-1 stub trade by stub-ifying the new API instead of the helpers it uses. The last remaining "single" stub will soon be dropped as well. [sean: rewrite changelog and comment, tag for stable, remove defunct stubs]

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00141 3rd percentileScored 2026-11-07
Fix Fixed Linux (Linux): 6.6.160, 6.12.86, 6.18.27 +2Red Hat: 2 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux6.2 and later6.6.160, 6.12.86, 6.18.27, 7.0.4, 7.1Patch availableCNA
  • Linux VendorLinux Affected 6.2 and later Fixed in 6.6.160, 6.12.86, 6.18.27, 7.0.4, 7.1 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*6.2 to before 6.12.86; 6.13 to before 6.18.27; 6.19 to before 7.0.4VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.2 to before 6.12.86; 6.13 to before 6.18.27; 6.19 to before 7.0.4 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 6.6.160, 6.12.86, 6.18.27, 7.0.4, 7.1

Red Hat 2 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-2026:72624 Released 2026-09-28 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.61.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.61.1.el10_2, kernel-64k-devel-6.12.0-211.61.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.61.1.el10_2, kernel-64k-6.12.0-211.61.1.el10_2, kernel-64k-core-6.12.0-211.61.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.61.1.el10_2, libperf-6.12.0-211.61.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.61.1.el10_2, kernel-rt-64k-6.12.0-211.61.1.el10_2, kernel-rt-64k-core-6.12.0-211.61.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.61.1.el10_2, kernel-rt-core-6.12.0-211.61.1.el10_2, kernel-rt-debug-6.12.0-211.61.1.el10_2 +9

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:72624
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:72624
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:72624
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:72624
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:72624
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:76739
Not affected: 4 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-46076
  2. 2026-10-03 Alias added: GHSA-gj33-hwgc-v3v8
  3. 2026-10-09 Fix available: RHSA-2026:76739 · Red Hat
  4. 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
  5. 2026-10-16 CISA SSVC decision points changed
  6. 2026-10-19 Weakness changed · CISA ADP
  7. 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@fcef67506c0234935cb0fb026740a637edb58d7c · CNA
  8. 2026-10-21 1 new reference · CNA
  9. 2026-10-30 Affected versions changed · Red Hat

References

Patch 4

Other 1

  • 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-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
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

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