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VulnerabilityPublished Updated

CVE-2026-31680: Linux kernel · Use After Free

Affects Linux kernelSource CVE Database V5

0

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

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ d3aedd5ebd4b0b925b0bcda548066803e1318499, < 8027964931785cb73d520ac70a342a3dc16c249b
Fixed in
  • 8027964931785cb73d520ac70a342a3dc16c249b
LinuxLinuxAffected
  • ≥ d3aedd5ebd4b0b925b0bcda548066803e1318499, < 414726b69921fe6355ae453f5b35e68dd078342a
Fixed in
  • 414726b69921fe6355ae453f5b35e68dd078342a
LinuxLinuxAffected
  • ≥ d3aedd5ebd4b0b925b0bcda548066803e1318499, < 572ce62778519a7d4d1c15f55dd2e45a474133c4
Fixed in
  • 572ce62778519a7d4d1c15f55dd2e45a474133c4
LinuxLinuxAffected
  • ≥ d3aedd5ebd4b0b925b0bcda548066803e1318499, < 9ca562bb8e66978b53028fa32b1a190708e6a091
Fixed in
  • 9ca562bb8e66978b53028fa32b1a190708e6a091
LinuxLinuxAffected
  • ≥ d3aedd5ebd4b0b925b0bcda548066803e1318499, < 6c7fbdb8ffde6413640de7cfbd7c976c353e89f8
Fixed in
  • 6c7fbdb8ffde6413640de7cfbd7c976c353e89f8
LinuxLinuxAffected
  • ≥ d3aedd5ebd4b0b925b0bcda548066803e1318499, < 5a6b15f861b7c1304949e3350d23490a5fe429fd
Fixed in
  • 5a6b15f861b7c1304949e3350d23490a5fe429fd

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

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