Race Condition The advisory has been revoked - it doesn't affect any version of package perf (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CENTOS6-PERF-16164716
- published23 Apr 2026
- disclosed22 Apr 2026
Introduced: 22 Apr 2026
CVE-2026-31504 (opens in a new tab)Amendment
The Centos security team deemed this advisory irrelevant for Centos:6.
NVD Description
Note: Versions mentioned in the description apply only to the upstream perf package and not the perf package as distributed by Centos.
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.
References
- https://access.redhat.com/security/cve/CVE-2026-31504
- https://git.kernel.org/stable/c/1b4c03f8892d955385c202009af7485364731bb9
- https://git.kernel.org/stable/c/42156f93d123436f2a27c468f18c966b7e5db796
- https://git.kernel.org/stable/c/42cfd7898eeed290c9fb73f732af1f7d6b0a703e
- https://git.kernel.org/stable/c/654386baef228c2992dbf604c819e4c7c35fc71b
- https://git.kernel.org/stable/c/75fe6db23705a1d55160081f7b37db9665b1880b
- https://git.kernel.org/stable/c/ceccbfc6de720ad633519a226715989cfb065af1
- https://git.kernel.org/stable/c/d0c7cdc15fdf8c4f91aca1928e52295d175b6ec6
- https://git.kernel.org/stable/c/ee642b1962caa9aa231c01abbd58bc453ae6b66e