CVE-2026-72405

Summary

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

net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync

Yue Sun reported a use-after-free and debugobjects warning in udp_tunnel_nic_device_sync_work() during concurrent device operations.

The workqueue core clears the internal pending bit before invoking the worker. At that point, a concurrent thread can queue the work again. When the already running worker eventually clears the work_pending flag to 0, it mistakenly clears the flag for the newly queued instance. udp_tunnel_nic_unregister() then observes work_pending as 0 and frees the structure while the second work item is still active in the queue, leading to UAF.

Fix this by returning early in udp_tunnel_nic_device_sync() if work_pending is already set, preventing redundant work queueing.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/cee6688e5731c0591643521716d1a1a5c1a98bf8
• https://git.kernel.org/stable/c/9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7
• https://git.kernel.org/stable/c/54292b167466cdf42176b7b6f01da66c184deb12
• https://git.kernel.org/stable/c/ecf69d4b43370c587e48d4d70289dbdb7e039d4d

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