CVE-2026-43384: net/tcp-ao: Fix MAC comparison to be constant-time

CVE-2026-43384: net/tcp-ao: Fix MAC comparison to be constant-time

[Greg Kroah-Hartman]

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

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

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

net/tcp-ao: Fix MAC comparison to be constant-time

To prevent timing attacks, MACs need to be compared in constant
time.  Use the appropriate helper function for this.

The Linux kernel CVE team has assigned CVE-2026-43384 to this issue.


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

	Issue introduced in 6.7 with commit 0a3a809089eb1d4a0a2fd0c16b520d603988c859 and fixed in 6.12.78 with commit 8be6ed64966da48b6c4726918f106c18742a5125
	Issue introduced in 6.7 with commit 0a3a809089eb1d4a0a2fd0c16b520d603988c859 and fixed in 6.18.19 with commit a269cbdc442f8658bca35383e34b9d0b0ff95a1c
	Issue introduced in 6.7 with commit 0a3a809089eb1d4a0a2fd0c16b520d603988c859 and fixed in 6.19.9 with commit 080b0e210088296dd50d6637c06c1db14246adfe
	Issue introduced in 6.7 with commit 0a3a809089eb1d4a0a2fd0c16b520d603988c859 and fixed in 7.0 with commit 67edfec516d30d3e62925c397be4a1e5185802fc

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-2026-43384
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/ipv4/Kconfig
	net/ipv4/tcp_ao.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/8be6ed64966da48b6c4726918f106c18742a5125
	https://git.kernel.org/stable/c/a269cbdc442f8658bca35383e34b9d0b0ff95a1c
	https://git.kernel.org/stable/c/080b0e210088296dd50d6637c06c1db14246adfe
	https://git.kernel.org/stable/c/67edfec516d30d3e62925c397be4a1e5185802fc