CVE-2026-46131: Linux kernel · KVM: x86: check for nEPT/nNPT in slow flush hypercalls
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1061.64~22.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1061.64~22.04.1, 6.8.0-1063.71~22.04.1, 6.8.0-1062.69~22.04.1 +45
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 28 May 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
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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 patch is available and should be applied to affected Linux kernel versions to resolve this vulnerability. The vendor advisory from Ubuntu confirms that fixes have been released. Users should update to the fixed kernel versions as specified by their distribution. No additional mitigation is required beyond applying the official kernel updates.
Description
A vulnerability in the Linux kernel's KVM x86 subsystem related to incorrect checks for nested EPT/NPT in slow flush hypercalls has been resolved. The flaw involved improper validation of guest mode status, which could affect nested virtualization scenarios. This issue has been fixed in updated Linux kernel versions. The vulnerability has a medium severity rating with a CVSS score of 5.5 and does not impact confidentiality or integrity but affects availability. No known exploits are reported in the wild. Multiple affected Linux kernel versions are identified, and patches are available.
References
- ubuntu.com/security/CVE-2026-46131 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-46131 (opens in a new tab)
- git.kernel.org/linus/464af6fc2b1dcc74005b7f58ee3812b17777efee (opens in a new tab)
- git.kernel.org/stable/c/45fc766bc756ff1d66f8ca026a9c4f7f764adfae (opens in a new tab)
- git.kernel.org/stable/c/464af6fc2b1dcc74005b7f58ee3812b17777efee (opens in a new tab)
- git.kernel.org/stable/c/4c7f8436b19a2a3acc0cb6b6e3becd6796ae5c57 (opens in a new tab)
- git.kernel.org/stable/c/971f17f5d91045404e3914029ea57c3da90179a4 (opens in a new tab)
- git.kernel.org/stable/c/d6f4e217d663ede5becc2fd6cb612c749677387b (opens in a new tab)
- ubuntu.com/security/notices/USN-8566-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8568-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8569-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8593-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8606-1 (opens in a new tab)