Medium [CVE-2026-74490] avoid use-after-free in poll trace queue dumps

In the Linux kernel, the following vulnerability has been resolved: tipc: avoid use-after-free in poll trace queue dumps TIPC socket tracepoints dump queue state through tipc_sk_dump().

Most queue-dump callsites already serialize that walk under the socket lock or sk->sk_lock.slock, but tipc_poll() calls trace_tipc_sk_poll(..., TIPC_DUMP_ALL,...) without holding either lock.

That lets the poll trace path reach tipc_list_dump() and backlog head/tail dumping while another context dequeues and frees an skb, leaving the trace helper dereferencing a stale queue entry. Stop the unlocked poll trace site from requesting queue dumps.

Other queue dump trace callsites keep their existing output under the locking they already provide, while poll still emits the event itself without walking live queue members from an unlocked context. A flaw was found in the Linux kernel's TIPC (Transparent Inter-Process Communication) module.

A race condition exists in the `tipc_poll()` function when dumping trace queue state, as it does not properly hold necessary locks. This allows a local attacker to trigger a use-after-free vulnerability by causing the system to access memory that has already been freed.

This could lead to a denial of service or other unpredictable system behavior. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

Weakness: CWE-825.