SB2026081514 - Use-after-free in Linux kernel rxrpc

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-74434)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause memory corruption and trigger a use-after-free.

The vulnerability exists due to a use-after-free in rxrpc_recvmsg_oob() when processing an out-of-band message with MSG_PEEK. A local user can read a challenge with MSG_PEEK so that the same sk_buff becomes reachable from both queues to cause memory corruption and trigger a use-after-free.

The issue occurs because the message remains on recvmsg_oobq while also being added to pending_oobq, and the resulting queue corruption is triggered when the socket is closed and both queues are drained.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/5801cff7d5d7b4e9d877dfb627b23eb63167f02c
• https://git.kernel.org/stable/c/5f470cc883416fea6d3bce18ef96bf91dd49ffc3
• https://git.kernel.org/stable/c/9ada3931beb37068fcb725b34b0398457009f343