Race Condition Affecting kernel-tools package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

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  • Snyk IDSNYK-CENTOS8-KERNELTOOLS-16154769
  • published23 Apr 2026
  • disclosed22 Apr 2026

Introduced: 22 Apr 2026

NewCVE-2026-31504  (opens in a new tab)
CWE-364  (opens in a new tab)

How to fix?

There is no fixed version for Centos:8 kernel-tools.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-tools package and not the kernel-tools package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

net: fix fanout UAF in packet_release() via NETDEV_UP race

packet_release() has a race window where NETDEV_UP can re-register a socket into a fanout group's arr[] array. The re-registration is not cleaned up by fanout_release(), leaving a dangling pointer in the fanout array. packet_release() does NOT zero po->num in its bind_lock section. After releasing bind_lock, po->num is still non-zero and po->ifindex still matches the bound device. A concurrent packet_notifier(NETDEV_UP) that already found the socket in sklist can re-register the hook. For fanout sockets, this re-registration calls __fanout_link(sk, po) which adds the socket back into f->arr[] and increments f->num_members, but does NOT increment f->sk_ref.

The fix sets po->num to zero in packet_release while bind_lock 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.

CVSS Base Scores

version 3.1