CVE-2026-74270

In the Linux kernel, the following vulnerability has been resolved:

handshake: Require admin permission for DONE command

ACCEPT and DONE are the two downcalls of the handshake genl

family, both intended for use by the trusted handshake agent

(tlshd). ACCEPT already requires GENL_ADMIN_PERM; DONE has

no privilege check at all.

The fd-lookup in handshake_nl_done_doit() only confirms that

some pending handshake request exists for the supplied sockfd;

it does not authenticate the sender. An unprivileged process

that guesses or observes a valid sockfd can therefore submit

a DONE with HANDSHAKE_A_DONE_STATUS == 0, leaving the kernel

consumer to proceed as if the handshake succeeded. A non-zero

status on a forged DONE tears down a legitimate in-flight

handshake before tlshd can report its real result.