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CVE-2026-68338

net/packet: avoid fanout hook re-registration after unregister

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From dc99f600698dcac69b8f56dda9a8a00d645c5ffc · fixed in acb40ebfa5c4d62f84339fcbf713f2a9fd033a71; From dc99f600698dcac69b8f56dda9a8a00d645c5ffc · fixed in c820f4b7f2fa38f8769db0d0cefdd94e2721504d; From dc99f600698dcac69b8f56dda9a8a00d645c5ffc · fixed in 4628efbdc7affd094181f5263e65c1062e31f15f; From dc99f600698dcac69b8f56dda9a8a00d645c5ffc · fixed in 80ec024d53a05c60ad1d08968dcf745f10c1665c; From dc99f600698dcac69b8f56dda9a8a00d645c5ffc · fixed in 0a052e0808e015e68144a9877e6ef42b952c49fa; From dc99f600698dcac69b8f56dda9a8a00d645c5ffc · fixed in 1bc55c29cd85818e9052f17deb287d5a11fb817f; From dc99f600698dcac69b8f56dda9a8a00d645c5ffc · fixed in a885387dae7986a55bae5c77a15bdd447f64e9b9; From dc99f600698dcac69b8f56dda9a8a00d645c5ffc · fixed in 50aff80475abd3533eef4320477037e6fcc6b56e

  • Linux Linux

    3.1

  • KernelLinux

    From 3.1.0 · fixed in 5.10.265; From 5.11.0 · fixed in 5.15.216; From 5.16.0 · fixed in 6.1.183; From 6.2.0 · fixed in 6.6.148; From 6.7.0 · fixed in 6.12.101; From 6.13.0 · fixed in 6.18.42; From 6.19.0 · fixed in 7.1.6

References 8

git.kernel.org