CVE-2026-74688

Summary

In the Linux kernel, the following vulnerability has been resolved:

sctp: clear control chunk transport if it is being removed

sctp_make_heartbeat_ack() caches the destination transport in chunk->transport without taking a reference. When src_out_of_asoc_ok is enabled, the HEARTBEAT ACK may remain queued on control_chunk_list instead of being transmitted immediately.

If the peer transport is removed while the chunk is still queued, sctp_assoc_rm_peer() drops the transport and schedules it for RCU freeing, but only clears cached transport pointers in out_chunk_list. The queued control chunk therefore retains a dangling transport pointer.

Once an ASCONF_ACK clears the suppression and the queued control chunk is transmitted, SCTP dereferences the stale transport pointer, leading to a use-after-free.

Fix this by also clearing chunk->transport for queued control chunks in control_chunk_list when removing the transport.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/dbb3f418a8665ffb0514e1a9520ab6a1c5d4d886
• https://git.kernel.org/stable/c/fad4766a74220fe579c6fcaa10ba01c23529814f
• https://git.kernel.org/stable/c/936658ec41c28c397ef390140e02d4c91ade92f0
• https://git.kernel.org/stable/c/8de65194a04d2552cd39b6c67d942d490f22d174
• https://git.kernel.org/stable/c/6160e756db81d6cb63e3e2952efcf6c5134be385
• https://git.kernel.org/stable/c/18d704bdd809377dfd81a3c2f42426763b5da227
• https://git.kernel.org/stable/c/4d6b9cac6df5e0cfef1a66b3edd7aebdb9e4b7e7
• https://git.kernel.org/stable/c/c9158ceaf27780ef64534ad72f44ffde3f8ccc49

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