CVE-2026-45918 (GCVE-0-2026-45918)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:17 – Updated: 2026-05-27 12:17
VLAI
Title
ovpn: tcp - don't deref NULL sk_socket member after tcp_close()
Summary
In the Linux kernel, the following vulnerability has been resolved: ovpn: tcp - don't deref NULL sk_socket member after tcp_close() When deleting a peer in case of keepalive expiration, the peer is removed from the OpenVPN hashtable and is temporary inserted in a "release list" for further processing. This happens in: ovpn_peer_keepalive_work() unlock_ovpn(release_list) This processing includes detaching from the socket being used to talk to this peer, by restoring its original proto and socket ops/callbacks. In case of TCP it may happen that, while the peer is sitting in the release list, userspace decides to close the socket. This will result in a concurrent execution of: tcp_close(sk) __tcp_close(sk) sock_orphan(sk) sk_set_socket(sk, NULL) The last function call will set sk->sk_socket to NULL. When the releasing routine is resumed, ovpn_tcp_socket_detach() will attempt to dereference sk->sk_socket to restore its original ops member. This operation will crash due to sk->sk_socket being NULL. Fix this race condition by testing-and-accessing sk->sk_socket atomically under sk->sk_callback_lock.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 11851cbd60ea1e5abbd97619d69845ead99303d6 , < f998b2c4bec487063a586695159f9a1856e81c56 (git)
Affected: 11851cbd60ea1e5abbd97619d69845ead99303d6 , < b9142cf4e066c825ec68752a7dcaceda700bbe26 (git)
Affected: 11851cbd60ea1e5abbd97619d69845ead99303d6 , < 94560267d6c41b1ff3fafbab726e3f8a55a6af34 (git)
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Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.14 , ≤ 6.18.* (semver)
Unaffected: 6.19.4 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: tcp - don\u0027t deref NULL sk_socket member after tcp_close()\n\nWhen deleting a peer in case of keepalive expiration, the peer is\nremoved from the OpenVPN hashtable and is temporary inserted in a\n\"release list\" for further processing.\n\nThis happens in:\novpn_peer_keepalive_work()\n  unlock_ovpn(release_list)\n\nThis processing includes detaching from the socket being used to\ntalk to this peer, by restoring its original proto and socket\nops/callbacks.\n\nIn case of TCP it may happen that, while the peer is sitting in\nthe release list, userspace decides to close the socket.\nThis will result in a concurrent execution of:\n\ntcp_close(sk)\n  __tcp_close(sk)\n    sock_orphan(sk)\n      sk_set_socket(sk, NULL)\n\nThe last function call will set sk-\u003esk_socket to NULL.\n\nWhen the releasing routine is resumed, ovpn_tcp_socket_detach()\nwill attempt to dereference sk-\u003esk_socket to restore its original\nops member. This operation will crash due to sk-\u003esk_socket being NULL.\n\nFix this race condition by testing-and-accessing\nsk-\u003esk_socket atomically under sk-\u003esk_callback_lock."
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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