Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Search

DEBIAN-CVE-2026-31504

HighCVSS 7.8 / 10
Published Apr 22, 2026·Last modified Jun 15, 2026
Affected Components(0)

No affected components available

Description

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.

Risk Scores
Base Score
7.8

The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
7.1

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities
  • CVE-2026-31504
    Upstream
  • EUVD-2026-24881
    Upstream

Browse More

Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard