CVE-2026-72404

Technical Description

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

tipc: fix UAF in cleanup_bearer() due to premature dst_cache_destroy()

TIPC UDP media bearer teardown calls dst_cache_destroy() on its

replicast caches before calling synchronize_net() to wait for

concurrent RCU readers (transmitters) to finish:

static void cleanup_bearer(struct work_struct *work)

{

...

list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {

dst_cache_destroy(&rcast->dst_cache);

list_del_rcu(&rcast->list);

kfree_rcu(rcast, rcu);

}

...

dst_cache_destroy(&ub->rcast.dst_cache);

udp_tunnel_sock_release(ub->sk);

synchronize_net();

...

}

This is highly buggy because dst_cache_destroy() immediately frees the

per-CPU cache memory (free_percpu()) and releases the cached dst

entries without any synchronization.

If a concurrent transmitter (e.g., tipc_udp_xmit()) is running on another

CPU under RCU protection, it can call dst_cache_get() concurrently,

leading to:

1. Use-After-Free on the per

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References