ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-31504

In the Linux kernel, the following vulnerability has been resolved: net: fix fanout UAF in packet_release() via NETDEV_UP race has a race window where can re-register…

Published Apr 22, 2026 · catalog updated Oct 15, 2026 · linux kernel

Check if you run it

No confirmed exploitation is on record for CVE-2026-31504. EPSS is 0.14%. Act only if a listed version of linux kernel is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.14%
Remediation
Advisory link
Affected products
cpe linux/linux kernel

In the Linux kernel, the following vulnerability has been resolved: net: fix fanout UAF in packet_release() via NETDEV_UP race has a race window where can re-register a socket into a fanout group's array. The re-registration is not cleaned up by , leaving a dangling pointer in the fanout array. does NOT zero in its section. After releasing , is still non-zero and still matches the bound device. A concurrent that already found the socket in can re-register the hook. For fanout sockets, this re-registration calls which adds the socket back into and increments , but does NOT increment . The fix sets to zero in while is held to prevent NETDEV_UP from linking, preventing the race window. This bug was found following an additional audit with Claude Code based on CVE-2025-38617.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe linux/linux kernel3.1

How to fix CVE-2026-31504

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-31504. EPSS is 0.14%. Act only if a listed version of linux kernel is installed.

Which versions are affected?

Compare what you have installed with linux/linux kernel 3.1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-416: Use After Free. EPSS 0.14%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 22, 2026 · NIST NVD

    Detected

    In the Linux kernel, the following vulnerability has been resolved: net: fix fanout UAF in packet_release() via NETDEV_UP race has a race window where can re-register a socket into a fanout group's array. The re-registration is not cleaned up by , leaving a dangling pointer in the fanout array. does NOT zero in its section. After releasing , is still non-zero and still matches the bound device. A

  2. Oct 15, 2026 · NIST NVD

    Updated

    In the Linux kernel, the following vulnerability has been resolved: net: fix fanout UAF in packet_release() via NETDEV_UP race has a race window where can re-register a socket into a fanout group's array. The re-registration is not cleaned up by , leaving a dangling pointer in the fanout array. does NOT zero in its section. After releasing , is still non-zero and still matches the bound device. A

Sources

  • CVE.orgVulnerability recordCVE-2026-31504

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-31504

    30-day exploitation probability 0.1%

    first.org
  • NIST NVDVulnerability recordCVE-2026-31504

    In the Linux kernel, the following vulnerability has been resolved: net: fix fanout UAF in packet_release() via NETDEV_UP race has a race window where can re-register a socket into a fanout group's array. The re-registration is not cleaned

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.