CVE-2026-99082: Linux kernel · KVM: x86: Use active memslots for the per-vCPU MMIO cache
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 28 Oct 2026, 01:30 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that corrects the caching and validation logic to use the vCPU's active memslots, properly distinguishing between normal and SMM address spaces. Users should apply the updated Linux kernel versions that include this fix. No additional mitigation steps are indicated beyond applying the official patch.
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 memslot generations. The flaw involves improper use of memslots when the vCPU runs in System Management Mode (SMM), which can lead to stale cache entries and incorrect memory accesses. This can cause KVM to bypass write-tracking for certain memory pages, potentially allowing continued use of outdated shadow translations. The issue has been fixed by ensuring the active memslots are used for caching and validation, distinguishing between normal and SMM address spaces.
References
- ubuntu.com/security/CVE-2026-99082 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99082 (opens in a new tab)
- git.kernel.org/stable/c/2566780c684c9c21241d409d790087c73070f312 (opens in a new tab)
- git.kernel.org/stable/c/7fd4e64f4bbc8c35ae8f0d2a1fb5b77a76d5b4fd (opens in a new tab)
- git.kernel.org/stable/c/a63f79d9da9468952396af73e1e53330845cf876 (opens in a new tab)
- git.kernel.org/stable/c/b3e6212dea2e4328a841ceb37f377583176dc735 (opens in a new tab)
- git.kernel.org/stable/c/e792a9ace39d2812a5b342a1987186c7bc653204 (opens in a new tab)