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VulnerabilityPublished Updated

CVE-2026-99082: Linux kernel · KVM: x86: Use active memslots for the per-vCPU MMIO cache

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High · fixed in e792a9ace39d2812a5b342a1987186c7bc653204 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in e792a9ace39d2812a5b342a1987186c7bc653204, b3e6212dea2e4328a841ceb37f377583176dc735, a63f79d9da9468952396af73e1e53330845cf876 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 699023e239658e62da6f42f47d31b54788521ec1, < e792a9ace39d2812a5b342a1987186c7bc653204
Fixed in
  • e792a9ace39d2812a5b342a1987186c7bc653204
LinuxLinuxAffected
  • ≥ 699023e239658e62da6f42f47d31b54788521ec1, < b3e6212dea2e4328a841ceb37f377583176dc735
Fixed in
  • b3e6212dea2e4328a841ceb37f377583176dc735
LinuxLinuxAffected
  • ≥ 699023e239658e62da6f42f47d31b54788521ec1, < a63f79d9da9468952396af73e1e53330845cf876
Fixed in
  • a63f79d9da9468952396af73e1e53330845cf876
LinuxLinuxAffected
  • ≥ 699023e239658e62da6f42f47d31b54788521ec1, < 2566780c684c9c21241d409d790087c73070f312
Fixed in
  • 2566780c684c9c21241d409d790087c73070f312
LinuxLinuxAffected
  • ≥ 699023e239658e62da6f42f47d31b54788521ec1, < 7fd4e64f4bbc8c35ae8f0d2a1fb5b77a76d5b4fd
Fixed in
  • 7fd4e64f4bbc8c35ae8f0d2a1fb5b77a76d5b4fd
LinuxLinuxAffected
  • =4.2
Fixed in–

AI-suggested

This vulnerability has been fixed in mainline Linux kernel versions identified by the provided commit hashes. Users and administrators should update their Linux kernels to versions including these fixes to resolve the issue. No additional mitigations are required once the kernel is patched.

Description

CVE-2026-99082 is a vulnerability in the Linux kernel's KVM x86 virtualization component related to the handling of per-vCPU MMIO cache and memslots in System Management Mode (SMM). The flaw allows stale MMIO cache entries from the SMM address space to remain valid after switching back to the normal address space, potentially causing incorrect memory writes that bypass KVM's write-tracking mechanisms. This can lead to inconsistent nested EPT table states and trigger kernel warnings. The issue is fixed by using the active memslots for caching and validation, ensuring proper separation of address spaces.

References

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