{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72243", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.914Z", "datePublished": "2026-08-15T05:54:31.117Z", "dateUpdated": "2026-08-18T06:56:32.099Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-18T06:56:32.099Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: check connect-related permissions on TCP Fast Open\n\nSimilar to Landlock, SELinux was not updated when TCP Fast Open\nsupport was introduced to ensure connect-related permissions are\nchecked when using TCP Fast Open. Update its socket_sendmsg() hook to\ncall selinux_socket_connect() when MSG_FASTOPEN is passed." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N", "baseScore": 8.4, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation requires a confined local process to invoke sendmsg(2)/sendto(2) with MSG_FASTOPEN; the vulnerable selinux_socket_sendmsg() LSM hook runs on the syscall path before TCP fast-open performs its implicit connect.\nAC:L - A confined task with SOCKET__WRITE can reliably trigger the bypass with one sendmsg/sendto using MSG_FASTOPEN and a destination address; TFO client is enabled by default (sysctl_tcp_fastopen=TFO_CLIENT_ENABLE) and no race or special victim state is needed.\nPR:L - The attacker must be an unprivileged process in a SELinux domain that grants socket write but denies connect/name_connect (e.g., confined Android apps, container workloads, hardened service domains); no real root or init-namespace privileges are required.\nUI:N - No victim interaction is required; the confined attacker process directly issues the bypassing syscall without needing another user or administrator to perform any action.\nS:C - Successful exploitation crosses the SELinux MAC confinement boundary, allowing a sandboxed domain to establish outbound TCP/MPTCP connections that connect(2) and name_connect policy would have blocked, escaping the intended network policy scope.\nC:H - Bypassing connect and name_connect mediation lets a confined process open TCP/MPTCP sessions to SELinux-forbidden destinations and read arbitrary response data from those services (internal APIs, metadata endpoints, databases), constituting unauthorized information disclosure.\nI:H - The bypass enables unauthorized outbound connection establishment and transmission of arbitrary application data (including SYN-cookie payload) to hosts and ports explicitly denied by SELinux connect/name_connect rules, violating integrity of the confinement policy.\nA:N - This is a pure SELinux LSM policy-bypass flaw with no kernel memory corruption, panic, oops, hang, or resource exhaustion; exploitation does not impact system availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "security/selinux/hooks.c" ], "versions": [ { "version": "cf60af03ca4e71134206809ea892e49b92a88896", "lessThan": "11406d0d7e11b4e525bb2ace2c70107031d058da", "status": "affected", "versionType": "git" }, { "version": "cf60af03ca4e71134206809ea892e49b92a88896", "lessThan": "e507633bf76bccf1a6af27771fb0d6e2862b7eac", "status": "affected", "versionType": "git" }, { "version": "cf60af03ca4e71134206809ea892e49b92a88896", "lessThan": "d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3", "status": "affected", "versionType": "git" }, { "version": "cf60af03ca4e71134206809ea892e49b92a88896", "lessThan": "fc633a598206d4f23af782db7c0b5f3a82751d2c", "status": "affected", "versionType": "git" }, { "version": "cf60af03ca4e71134206809ea892e49b92a88896", "lessThan": "646ebbc5f2ff9147d084e1213143f091026a611c", "status": "affected", "versionType": "git" }, { "version": "cf60af03ca4e71134206809ea892e49b92a88896", "lessThan": "44c74d27d1b9aaa99fa8a83640c1223575262b80", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "security/selinux/hooks.c" ], "versions": [ { "version": "3.6", "status": "affected" }, { "version": "0", "lessThan": "3.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "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": "3.6", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.6", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/11406d0d7e11b4e525bb2ace2c70107031d058da" }, { "url": "https://git.kernel.org/stable/c/e507633bf76bccf1a6af27771fb0d6e2862b7eac" }, { "url": "https://git.kernel.org/stable/c/d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3" }, { "url": "https://git.kernel.org/stable/c/fc633a598206d4f23af782db7c0b5f3a82751d2c" }, { "url": "https://git.kernel.org/stable/c/646ebbc5f2ff9147d084e1213143f091026a611c" }, { "url": "https://git.kernel.org/stable/c/44c74d27d1b9aaa99fa8a83640c1223575262b80" } ], "title": "selinux: check connect-related permissions on TCP Fast Open", "x_generator": { "engine": "bippy-1.2.0" } } } }