CVE-2026-63828 - apparmor: mediate the implicit connect of TCP fast open sendmsg

CVE-2026-63828 - apparmor: mediate the implicit connect of TCP fast open sendmsg

https://cvefeed.io/rssfeed/latest.atom / Sun, 07/19/2026 - 16:06
CVE ID :CVE-2026-63828
Published : July 19, 2026, 12:16 p.m. | 32 minutes ago
Description :In the Linux kernel, the following vulnerability has been resolved: apparmor: mediate the implicit connect of TCP fast open sendmsg sendmsg()/sendto() with MSG_FASTOPEN is a combination of connect(2) and write(2): it opens the connection in the SYN. apparmor_socket_sendmsg() only checks AA_MAY_SEND, so a profile that grants send but denies connect lets a confined task open an outbound TCP/MPTCP connection that connect(2) would have refused, bypassing connect mediation. Mediate the implicit connect when MSG_FASTOPEN is set and a destination is supplied. Add it to apparmor_socket_sendmsg() (not the shared aa_sock_msg_perm() helper, which recvmsg also uses) and call aa_sk_perm() directly, mirroring the selinux and tomoyo fixes. sk_is_tcp() does not cover MPTCP fast open, so the SOCK_STREAM/IPPROTO_MPTCP arm is explicit.
Severity: 0.0 | NA
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