VulnerabilityPublished 24 Apr 2026Updated 6 Nov 2026

CVE-2026-31591: Linux kernel · KVM: SEV: Lock all vCPUs when synchronzing VMSAs for SNP launch finish

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in cb923ee6a80f4e604e6242a4702b59251e61a380 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:04 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in cb923ee6a80f4e604e6242a4702b59251e61a380, c87938fc7d99a06a7e5477c45b4e5a4148f85d66, 30fd9d8c82087742168db779929d8be0459b0716 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to cb923ee6a80f4e604e6242a4702b59251e61a380, c87938fc7d99a06a7e5477c45b4e5a4148f85d66, 30fd9d8c82087742168db779929d8be0459b0716 or 4df77742e8b9a6b935bdf46f02fd0aca4d4ee7f5.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ ad27ce155566f2b4400fa865859834592bd18777, < cb923ee6a80f4e604e6242a4702b59251e61a380	Fixed in cb923ee6a80f4e604e6242a4702b59251e61a380
LinuxLinux	Affected ≥ ad27ce155566f2b4400fa865859834592bd18777, < c87938fc7d99a06a7e5477c45b4e5a4148f85d66	Fixed in c87938fc7d99a06a7e5477c45b4e5a4148f85d66
LinuxLinux	Affected ≥ ad27ce155566f2b4400fa865859834592bd18777, < 30fd9d8c82087742168db779929d8be0459b0716	Fixed in 30fd9d8c82087742168db779929d8be0459b0716
LinuxLinux	Affected ≥ ad27ce155566f2b4400fa865859834592bd18777, < 4df77742e8b9a6b935bdf46f02fd0aca4d4ee7f5	Fixed in 4df77742e8b9a6b935bdf46f02fd0aca4d4ee7f5
LinuxLinux	Affected =6.11	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Lock all vCPUs when synchronzing VMSAs for SNP launch finish Lock all vCPUs when synchronizing and encrypting VMSAs for SNP guests, as allowing userspace to manipulate and/or run a vCPU while its state is being synchronized would at best corrupt vCPU state, and at worst crash the host kernel. Opportunistically assert that vcpu->mutex is held when synchronizing its VMSA (the SEV-ES path already locks vCPUs).

References

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