{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74268", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.878Z", "datePublished": "2026-08-15T05:57:42.920Z", "dateUpdated": "2026-08-17T05:45:14.504Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:45:14.504Z" }, "descriptions": [ { "lang": "en", "value": "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 \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 \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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - Remote attackers reach inet_csk_prepare_for_forced_close() via the standard TCP input path (tcp_v4_rcv/tcp_v6_rcv → tcp_check_req → tcp_v4/v6_syn_recv_sock put_and_exit) while processing attacker-sent handshake packets in softirq, with no local access required.\nAC:L - Attackers control handshake completion and can repeatedly force child setup failures—e.g., MPTCP JOIN/sport-mismatch dispose_child paths, ENOMEM under connection pressure in __inet_inherit_port or MD5/AO copy, or chtls setup failure—making put_and_exit reachable without conditions outside their influence.\nPR:N - The receive path is pre-authentication TCP/MPTCP processing; no victim credentials or capabilities are required. Exploitation only needs network reachability to a listener whose admin already attached cgroup BPF sock_ops setting BPF_SOCK_OPS_STATE_CB_FLAG (common on Kubernetes/Cilium/cloud nodes).\nUI:N - No victim interaction is needed beyond normal exposure of a TCP listener; the attacker triggers the bug entirely by sending network packets that complete then fail child socket creation.\nS:U - Vulnerability impact stays within the kernel on the host receiving the traffic; it does not cross VM, container runtime, or IOMMU security boundaries and represents standard in-kernel memory/lock safety impact.\nC:H - Inherited BPF_SOCK_OPS_STATE_CB_FLAG causes tcp_call_bpf() to run on an unlocked, partially torn-down child socket; BPF helpers can read tcp_sock fields without proper locking, enabling unsynchronized kernel memory reads that could disclose sensitive data.\nI:H - tcp_call_bpf() marks is_locked_tcp_sock while the socket lock was dropped, allowing cgroup BPF sock_ops programs to call bpf_setsockopt and modify tcp_sock/kernel state during forced close, creating plausible memory corruption and control-flow compromise primitives.\nA:H - sock_owned_by_me() WARN fires on this path and concurrent BPF access during tcp_done()/inet_csk_destroy_sock() can cause kernel oops or panic; remote attackers can repeatedly trigger the softirq failure path for denial of service on internet-facing BPF-enabled servers." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/tcp.h", "net/ipv4/inet_connection_sock.c" ], "versions": [ { "version": "d44874910a26f3a8f81edf873a2473363f07f660", "lessThan": "ce311bd2e36596f0aa2c92ca86fb3e019ac57eae", "status": "affected", "versionType": "git" }, { "version": "d44874910a26f3a8f81edf873a2473363f07f660", "lessThan": "8874dafc9099bc49c2e5ebba030f85d276421f92", "status": "affected", "versionType": "git" }, { "version": "d44874910a26f3a8f81edf873a2473363f07f660", "lessThan": "990348e5bb457697c2f1f7f7b65154a3334d9d2b", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/tcp.h", "net/ipv4/inet_connection_sock.c" ], "versions": [ { "version": "4.16", "status": "affected" }, { "version": "0", "lessThan": "4.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ce311bd2e36596f0aa2c92ca86fb3e019ac57eae" }, { "url": "https://git.kernel.org/stable/c/8874dafc9099bc49c2e5ebba030f85d276421f92" }, { "url": "https://git.kernel.org/stable/c/990348e5bb457697c2f1f7f7b65154a3334d9d2b" } ], "title": "tcp: clear sock_ops cb flags before force-closing a child socket", "x_generator": { "engine": "bippy-1.2.0" } } } }