{"id":"CVE-2026-72243","state":"PUBLISHED","title":"selinux: check connect-related permissions on TCP Fast Open","description":"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.","publishedAt":"2026-08-15T05:54:31.117Z","updatedAt":"2026-10-16T18:45:04.616Z","severity":{"score":8.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"11406d0d7e11b4e525bb2ace2c70107031d058da","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"e507633bf76bccf1a6af27771fb0d6e2862b7eac","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"fc633a598206d4f23af782db7c0b5f3a82751d2c","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"646ebbc5f2ff9147d084e1213143f091026a611c","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"44c74d27d1b9aaa99fa8a83640c1223575262b80","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/selinux/hooks.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.6","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/selinux/hooks.c"]}],"references":["https://git.kernel.org/stable/c/11406d0d7e11b4e525bb2ace2c70107031d058da","https://git.kernel.org/stable/c/e507633bf76bccf1a6af27771fb0d6e2862b7eac","https://git.kernel.org/stable/c/d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3","https://git.kernel.org/stable/c/fc633a598206d4f23af782db7c0b5f3a82751d2c","https://git.kernel.org/stable/c/646ebbc5f2ff9147d084e1213143f091026a611c","https://git.kernel.org/stable/c/44c74d27d1b9aaa99fa8a83640c1223575262b80"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72243.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72243","state":"PUBLISHED","datePublished":"2026-08-15T05:54:31.117Z","dateUpdated":"2026-10-16T18:45:04.616Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-09T03:40:39.914Z"},"containers":{"cna":{"title":"selinux: check connect-related permissions on TCP Fast Open","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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"11406d0d7e11b4e525bb2ace2c70107031d058da","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"e507633bf76bccf1a6af27771fb0d6e2862b7eac","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"fc633a598206d4f23af782db7c0b5f3a82751d2c","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"646ebbc5f2ff9147d084e1213143f091026a611c","versionType":"git"},{"version":"cf60af03ca4e71134206809ea892e49b92a88896","status":"affected","lessThan":"44c74d27d1b9aaa99fa8a83640c1223575262b80","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/selinux/hooks.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.6","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/selinux/hooks.c"]}],"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"}],"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."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-18T06:56:32.099Z"},"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-72243","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:44:53.438037Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T18:45:04.616Z"}}]}}}