{"id":"CVE-2026-74268","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74268","summary":"tcp: clear sock_ops cb flags before force-closing a child socket","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: clear sock_ops cb flags before force-closing a child socket\n\nA child socket inherits the listener's bpf_sock_ops_cb_flags via\nsk_clone_lock(). If its setup fails in tcp_v4_syn_recv_sock() /\ntcp_v6_syn_recv_sock(), the child is freed through put_and_exit, where\ninet_csk_prepare_forced_close() drops the socket lock and tcp_done() runs\nwithout it.\n\nIf BPF_SOCK_OPS_STATE_CB_FLAG was inherited, tcp_done() -> tcp_set_state()\ncalls tcp_call_bpf(), which expects the lock and trips sock_owned_by_me():\n\n  WARNING: include/net/sock.h:1799 at tcp_set_state+0x433/0x550\n  RIP: 0010:tcp_set_state+0x433/0x550 include/net/sock.h:1799\n  Call Trace:\n   <IRQ>\n   tcp_done+0xba/0x250 net/ipv4/tcp.c:5095\n   tcp_v4_syn_recv_sock+0x850/0xa50 net/ipv4/tcp_ipv4.c:1787\n   tcp_check_req+0xf30/0x1360 net/ipv4/tcp_minisocks.c:926\n   tcp_v4_rcv+0x1047/0x1b50 net/ipv4/tcp_ipv4.c:2164\n   </IRQ>\n\nThe child is freed before it is ever established, so it should run no\nsock_ops callback. Clear its cb flags in inet_csk_prepare_for_destroy_sock(),\nthe common point for the IPv4, IPv6 and chtls forced-close paths and for the\nMPTCP ->syn_recv_sock() failure path (dispose_child), which reaches tcp_done()\non a child that was never established too.","published":"2026-08-15T05:57:42.920Z","modified":"2026-08-18T03:56:28.026734734Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.18.40"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/8874dafc9099bc49c2e5ebba030f85d276421f92"},{"type":"WEB","url":"https://git.kernel.org/stable/c/990348e5bb457697c2f1f7f7b65154a3334d9d2b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ce311bd2e36596f0aa2c92ca86fb3e019ac57eae"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74268.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74268"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:28.026734734Z"}}