{"id":"CVE-2026-45918","summary":"ovpn: tcp - don't deref NULL sk_socket member after tcp_close()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\novpn: tcp - don't 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.","modified":"2026-07-08T08:13:33.570905446Z","published":"2026-05-27T12:17:34.500Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45918.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/94560267d6c41b1ff3fafbab726e3f8a55a6af34"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b9142cf4e066c825ec68752a7dcaceda700bbe26"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f998b2c4bec487063a586695159f9a1856e81c56"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45918.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45918"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"11851cbd60ea1e5abbd97619d69845ead99303d6"},{"fixed":"f998b2c4bec487063a586695159f9a1856e81c56"},{"fixed":"b9142cf4e066c825ec68752a7dcaceda700bbe26"},{"fixed":"94560267d6c41b1ff3fafbab726e3f8a55a6af34"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45918.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.16.0"},{"fixed":"6.18.14"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45918.json"}}],"schema_version":"1.7.5"}