CVE-2026-68161: sctp: close UDP tunnel sockets during netns teardown

CVE-2026-68161: sctp: close UDP tunnel sockets during netns teardown

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

sctp: close UDP tunnel sockets during netns teardown

proc_sctp_do_udp_port() starts per-net SCTP UDP tunneling sockets when
net.sctp.udp_port is set, and stops/restarts them when the sysctl value
changes. The netns exit path does not stop these sockets, so a namespace
can be torn down while its SCTP UDP tunnel sockets are still installed.

Close the UDP tunnel sockets from sctp_ctrlsock_exit() after unregistering
the per-net sysctl table. This prevents new sysctl writes from racing in
while the sockets are being released, and closes the sockets before the
control socket is destroyed.

The Linux kernel CVE team has assigned CVE-2026-68161 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.11 with commit 046c052b475e7119b6a30e3483e2888fc606a2f8 and fixed in 6.6.151 with commit c6eb2d615210b80339548ab07c0230edaab9a6c7
	Issue introduced in 5.11 with commit 046c052b475e7119b6a30e3483e2888fc606a2f8 and fixed in 6.12.101 with commit 8ff78591d309c50a4fdab683b68dd8d512a270dd
	Issue introduced in 5.11 with commit 046c052b475e7119b6a30e3483e2888fc606a2f8 and fixed in 6.18.42 with commit 3bf0e349cbb4f975f35eb22753acc346b89c66a0
	Issue introduced in 5.11 with commit 046c052b475e7119b6a30e3483e2888fc606a2f8 and fixed in 7.1.6 with commit 37ff9794be48d0caa37687e04d09675f9c849121
	Issue introduced in 5.11 with commit 046c052b475e7119b6a30e3483e2888fc606a2f8 and fixed in 7.2-rc5 with commit ffb2bd7ade36ec4da32c46a6eddbf4515316d08c

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-68161
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/sctp/protocol.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/c6eb2d615210b80339548ab07c0230edaab9a6c7
	https://git.kernel.org/stable/c/8ff78591d309c50a4fdab683b68dd8d512a270dd
	https://git.kernel.org/stable/c/3bf0e349cbb4f975f35eb22753acc346b89c66a0
	https://git.kernel.org/stable/c/37ff9794be48d0caa37687e04d09675f9c849121
	https://git.kernel.org/stable/c/ffb2bd7ade36ec4da32c46a6eddbf4515316d08c