CVE-2026-31680: Linux kernel · Use After Free
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in 8027964931785cb73d520ac70a342a3dc16c249b : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:18 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% 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 8027964931785cb73d520ac70a342a3dc16c249b, 414726b69921fe6355ae453f5b35e68dd078342a, 572ce62778519a7d4d1c15f55dd2e45a474133c4 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 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
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
AI-suggested
A fix is available and has been applied in the Linux kernel. Users should update to a fixed kernel version that includes the patch deferring the freeing of the flowlabel option until RCU teardown. No additional mitigation is required once the system is updated.
Description
CVE-2026-31680 is a use-after-free vulnerability in the Linux kernel's IPv6 flowlabel implementation. The flaw occurs because the exclusive flowlabel option memory is freed prematurely while the flowlabel structure remains accessible, allowing concurrent readers to dereference freed memory and cause a kernel crash. This issue affects Linux kernel version 3.9 and has been fixed by deferring the freeing of the option memory until the RCU teardown phase.
References
- git.kernel.org/stable/c/4b6798024f7b2d535f3db1002c760143cdbd1bd3 (opens in a new tab)
- git.kernel.org/stable/c/3c54b66c83fb8fcbde8e6a7bf90b65856e39f827 (opens in a new tab)
- git.kernel.org/stable/c/5a6b15f861b7c1304949e3350d23490a5fe429fd (opens in a new tab)
- git.kernel.org/stable/c/6c7fbdb8ffde6413640de7cfbd7c976c353e89f8 (opens in a new tab)
- git.kernel.org/stable/c/8027964931785cb73d520ac70a342a3dc16c249b (opens in a new tab)
- git.kernel.org/stable/c/414726b69921fe6355ae453f5b35e68dd078342a (opens in a new tab)
- git.kernel.org/stable/c/572ce62778519a7d4d1c15f55dd2e45a474133c4 (opens in a new tab)
- git.kernel.org/stable/c/9ca562bb8e66978b53028fa32b1a190708e6a091 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)