CVE-2026-74255

/// Technical description

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

tipc: fix UAF in tipc_l2_send_msg()

Syzbot reported a slab-use-after-free in ipvlan_hard_header() when

called from tipc_l2_send_msg().

The root cause is that tipc_disable_l2_media() calls synchronize_net()

while b->media_ptr is still valid. This allows concurrent RCU readers

to obtain the device pointer after synchronize_net() has finished.

The pointer is cleared later in bearer_disable(), but without any

subsequent synchronization, allowing the device to be freed while

still in use by readers.

Fix this by clearing b->media_ptr in tipc_disable_l2_media() before

calling synchronize_net().

This is safe to do now because the call order in bearer_disable()

was reversed in 0d051bf93c06 ("tipc: make bearer packet filtering generic")

to call tipc_node_delete_links() (which needs the pointer) before

disable_media().

https: //lore.kernel.org/netdev/[email protected]/T/#u

/// 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