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 · updated Oct 15, 2026 · 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.
Timeline
Detection, updates, and resolution for this record.
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
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
Affected
- cpe linux/linux kernelversion unspecified
- cpe linux/linux kernel3.1
Sources
- CVE.orgCVE-2026-31504
Official CVE identifier
cve.org - NIST NVDCVE-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