CVE-2026-68338: Linux

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net/packet: avoid fanout hook re-registration after unregister packet_set_ring() temporarily detaches a socket from packet delivery while reconfiguring its ring. It records the previous running state, clears po->num, unregisters the protocol hook when needed, drops po->bind_lock, and later restores po->num and re-registers the hook from the saved was_running value. That unlocked window can race with NETDEV_UNREGISTER. The notifier can observe the socket as not running, skip __unregister_prot_hook(), and invalidate the per-socket binding by setting po->ifindex to -1 and clearing po->prot_hook.dev. A one-member fanout group can still retain its shared fanout hook device pointer. When packet_set_ring() resumes, re-registering solely from the stale was_running state can re-add the fanout hook after the device has been unregistered. Treat po->ifindex == -1 as an invalidated binding after reacquiring po->bind_lock. This is distinct from ifindex 0, the normal unbound/wildcard state: ifindex -1 marks an existing device binding that was invalidated when the device was unregistered. Restore po->num as before, but do not re-register the hook if device unregister already detached the socket.

Affected products

• Linux Linux: from 3.1, before 5.10.265 (fixed in 5.10.265); from 5.11, before 5.15.216 (fixed in 5.15.216); from 5.16, before 6.1.183 (fixed in 6.1.183); from 6.2, before 6.6.148 (fixed in 6.6.148); from 6.7, before 6.12.101 (fixed in 6.12.101); from 6.13, before 6.18.42 (fixed in 6.18.42); …

Published 2026-08-10. Last modified 2026-08-19.