Bug 2516992 (CVE-2026-74490)

Summary: CVE-2026-74490 kernel: tipc: avoid use-after-free in poll trace queue dumps
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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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.
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Description OSIDB Bzimport 2026-08-15 12:43:15 UTC 
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.
Comment 1 gkamathe 2026-08-21 09:05:07 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081538-CVE-2026-74490-d5a0@gregkh/T