CVE-2026-98846 sctp: check RCV_SHUTDOWN after the sendmsg connect wait

Not scored Published 18 Oct 2026 Updated 21 Oct 2026

A use-after-free vulnerability in the Linux kernel SCTP implementation allows attackers to cause denial of service or potentially execute code via crafted network packets.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-98846?

CVE-2026-98846 is an use after free vulnerability in Linux, published on 18 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Which versions are affected by CVE-2026-98846?

How do I fix CVE-2026-98846?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-98846 being exploited?

There is no known exploitation of CVE-2026-98846 in the wild and no public exploit code.

Sources

Also known as AZL-109110, BELL-CVE-2026-98846, DEBIAN-CVE-2026-98846, GHSA-gghw-9hqp-85hc, UBUNTU-CVE-2026-98846.