{"id":"CVE-2026-63828","summary":"apparmor: mediate the implicit connect of TCP fast open sendmsg","details":"In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: mediate the implicit connect of TCP fast open sendmsg\n\nsendmsg()/sendto() with MSG_FASTOPEN is a combination of connect(2) and\nwrite(2): it opens the connection in the SYN. apparmor_socket_sendmsg()\nonly checks AA_MAY_SEND, so a profile that grants send but denies connect\nlets a confined task open an outbound TCP/MPTCP connection that connect(2)\nwould have refused, bypassing connect mediation.\n\nMediate the implicit connect when MSG_FASTOPEN is set and a destination\nis supplied. Add it to apparmor_socket_sendmsg() (not the shared\naa_sock_msg_perm() helper, which recvmsg also uses) and call aa_sk_perm()\ndirectly, mirroring the selinux and tomoyo fixes. sk_is_tcp() does not\ncover MPTCP fast open, so the SOCK_STREAM/IPPROTO_MPTCP arm is explicit.","modified":"2026-07-21T03:47:32.984915159Z","published":"2026-07-19T12:02:22.644Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63828.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/07b71c342382b854ab8030b244aeab6a7228ad7d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/45ebb934ea50b436ce49b2f159f090dab0d7fa28"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4a69b83045d3195d5b9a9b053ad840ddb2998b4e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4d587cd8a72155089a627130bbd4716ec0856e21"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7f57428ce00891d26b0f087ef754a4d820ec83aa"},{"type":"WEB","url":"https://git.kernel.org/stable/c/faea60deaa05c76f0772650f42eafde12bd39d93"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63828.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63828"},{"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":"cf60af03ca4e71134206809ea892e49b92a88896"},{"fixed":"7f57428ce00891d26b0f087ef754a4d820ec83aa"},{"fixed":"faea60deaa05c76f0772650f42eafde12bd39d93"},{"fixed":"07b71c342382b854ab8030b244aeab6a7228ad7d"},{"fixed":"4a69b83045d3195d5b9a9b053ad840ddb2998b4e"},{"fixed":"45ebb934ea50b436ce49b2f159f090dab0d7fa28"},{"fixed":"4d587cd8a72155089a627130bbd4716ec0856e21"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63828.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.6.0"},{"fixed":"6.1.177"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.144"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.95"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.38"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63828.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N"}]}