CVE-2026-31588: Linux kernel · Use After Free
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.8 High · fixed in dc6a6c3db3a4eca7e747cfc46e22c08d016c68f7 : patch Linux kernel soon.
Data as of 26 Oct 2026, 15:59 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- 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
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in dc6a6c3db3a4eca7e747cfc46e22c08d016c68f7, b5a02d37eb0739f462fa12df449ab9b3480c783b, 52570e73d48f1c73836d37e594667117b4c2a5a8 +6
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 24 Apr 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 |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
A fix for this vulnerability is available and has been merged into the Linux kernel in multiple commits. Users should update their Linux kernel to a version that includes these fixes. No additional mitigation steps are required beyond applying the official patch.
Description
CVE-2026-31588 is a use-after-free vulnerability in the Linux kernel's KVM x86 MMIO emulation. It occurs when servicing emulated MMIO writes that split page boundaries and involve small write values stored on the stack. This flaw can lead to referencing freed stack memory during MMIO completion, potentially causing memory corruption or crashes. The issue has been fixed by copying small write values into a scratch field in the MMIO fragment instead of referencing the original stack variable directly.
References
- git.kernel.org/stable/c/019d0bd32b9a4646ba35d904907452039e2db700 (opens in a new tab)
- git.kernel.org/stable/c/4569c66dd9e94a22cd0796b6514a8b25ffff16a1 (opens in a new tab)
- git.kernel.org/stable/c/52570e73d48f1c73836d37e594667117b4c2a5a8 (opens in a new tab)
- git.kernel.org/stable/c/dc6a6c3db3a4eca7e747cfc46e22c08d016c68f7 (opens in a new tab)
- git.kernel.org/stable/c/b5a02d37eb0739f462fa12df449ab9b3480c783b (opens in a new tab)
- git.kernel.org/stable/c/22d2ff69d487a32a8b88f9c970120fc2daa08a77 (opens in a new tab)
- git.kernel.org/stable/c/2b83d91e9ae92fe1258d7040a32430bbb3bb7d6e (opens in a new tab)
- git.kernel.org/stable/c/3a7b6d75c8f85b09dea893f64a85a356bcf6c3fe (opens in a new tab)
- git.kernel.org/stable/c/0b16e69d17d8c35c5c9d5918bf596c75a44655d3 (opens in a new tab)