Skip to main content
VulnerabilityPublished Updated

CVE-2026-31403: Linux kernel · Use After Free

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in e7fcf179b82d3a3730fd8615da01b087cc654d0b : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 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 2% 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 e7fcf179b82d3a3730fd8615da01b087cc654d0b, e3d77f935639e6ae4b381c80464c31df998d61f4, db4a9f99b12a7ee1c19d86c83a3b752c7effa6c6 +4
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 3 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
  • ≥ 96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5, < e7fcf179b82d3a3730fd8615da01b087cc654d0b
Fixed in
  • e7fcf179b82d3a3730fd8615da01b087cc654d0b
LinuxLinuxAffected
  • ≥ 96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5, < e3d77f935639e6ae4b381c80464c31df998d61f4
Fixed in
  • e3d77f935639e6ae4b381c80464c31df998d61f4
LinuxLinuxAffected
  • ≥ 96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5, < db4a9f99b12a7ee1c19d86c83a3b752c7effa6c6
Fixed in
  • db4a9f99b12a7ee1c19d86c83a3b752c7effa6c6
LinuxLinuxAffected
  • ≥ 96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5, < d1a19217995df9c7e4118f5a2820c5032fef2945
Fixed in
  • d1a19217995df9c7e4118f5a2820c5032fef2945
LinuxLinuxAffected
  • ≥ 96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5, < c7f406fb341d6747634b8b1fa5461656e5e56076
Fixed in
  • c7f406fb341d6747634b8b1fa5461656e5e56076
LinuxLinuxAffected
  • ≥ 96d851c4d28de8cc83fe2bd5c6bc2eb8f253a6c5, < 76740c28050dc6db2f5550f1325b00a11bbb3255
Fixed in
  • 76740c28050dc6db2f5550f1325b00a11bbb3255

AI-suggested

This vulnerability has been fixed in the Linux kernel versions identified by the provided commit hashes. Users and administrators should update to a Linux kernel version that includes these fixes. No additional mitigations are required once the system is patched.

Description

CVE-2026-31403 is a high-severity vulnerability in the Linux kernel's NFSD subsystem. It involves improper handling of network namespace references for the /proc/fs/nfs/exports file descriptor. Without holding a reference to the network namespace, the kernel may free related cache structures prematurely, leading to use-after-free conditions when the file descriptor is accessed after the namespace is torn down. This flaw has been fixed in specific Linux kernel commits.

References

Community reviews

Loading reviews…