High 8.4Published Jul 19, 2026

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

Updated under an hour ago (Oct 28, 2026, 4:40 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 8.4 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Awaiting Analysis
Record last updated: Aug 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from cf60af03ca4e71134206809ea892e49b92a88896 before a16714e7cf2baa98ba2efddd5d6cbac641f4e76b; from cf60af03ca4e71134206809ea892e49b92a88896 before 20383429b56974507c465d016e5238b189f7a246; from cf60af03ca4e71134206809ea892e49b92a88896 before 7f57428ce00891d26b0f087ef754a4d820ec83aa; from cf60af03ca4e71134206809ea892e49b92a88896 before faea60deaa05c76f0772650f42eafde12bd39d93; from cf60af03ca4e71134206809ea892e49b92a88896 before 07b71c342382b854ab8030b244aeab6a7228ad7d; from cf60af03ca4e71134206809ea892e49b92a88896 before 4a69b83045d3195d5b9a9b053ad840ddb2998b4e; from cf60af03ca4e71134206809ea892e49b92a88896 before 45ebb934ea50b436ce49b2f159f090dab0d7fa28; from cf60af03ca4e71134206809ea892e49b92a88896 before 4d587cd8a72155089a627130bbd4716ec0856e21	CNA record

References

References

https://git.kernel.org/stable/c/a16714e7cf2baa98ba2efddd5d6cbac641f4e76b
https://git.kernel.org/stable/c/20383429b56974507c465d016e5238b189f7a246
https://git.kernel.org/stable/c/7f57428ce00891d26b0f087ef754a4d820ec83aa
https://git.kernel.org/stable/c/faea60deaa05c76f0772650f42eafde12bd39d93
https://git.kernel.org/stable/c/07b71c342382b854ab8030b244aeab6a7228ad7d
https://git.kernel.org/stable/c/4a69b83045d3195d5b9a9b053ad840ddb2998b4e
https://git.kernel.org/stable/c/45ebb934ea50b436ce49b2f159f090dab0d7fa28
https://git.kernel.org/stable/c/4d587cd8a72155089a627130bbd4716ec0856e21

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.