CVE-2026-98846

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

sctp: check RCV_SHUTDOWN after the sendmsg connect wait

sctp_wait_for_connect() drops the socket lock while it sleeps. An

out-of-the-blue ABORT can then be processed from the socket backlog and

unlink the association. If a concurrent shutdown(fd, SHUT_RD) sets

RCV_SHUTDOWN, the waiter breaks with err == 0 before checking

asoc->base.dead. Its final sctp_association_put() can then free the

association, leaving sctp_sendmsg_to_asoc() to continue with a dangling

pointer.

Check RCV_SHUTDOWN along with the wait error in sctp_sendmsg_to_asoc()

before using the association again. The check only accesses the socket,

so it needs no additional association reference. Return the existing

-ESRCH so that sctp_sendmsg() skips freeing a new association that may

already have been destroyed.

Keep sctp_wait_for_connect() unchanged to preserve its behavior for the

connect() caller.