CVE-2026-72136: xfrm: xfrm_interface: require CAP_NET_ADMIN in the device netns for changelink

CVE-2026-72136: xfrm: xfrm_interface: require CAP_NET_ADMIN in the device netns for changelink

[Greg Kroah-Hartman]

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

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

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

xfrm: xfrm_interface: require CAP_NET_ADMIN in the device netns for changelink

xfrmi_changelink() operates on at most two netns, dev_net(dev) and the
interface link netns xi->net. They differ once the device is created in
or moved to a netns other than the one the request runs in. The rtnl
changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a
caller privileged there but not in xi->net can rewrite an interface that
lives in xi->net.

Gate xfrmi_changelink() on rtnl_dev_link_net_capable() at its top,
before any attribute is parsed.

The Linux kernel CVE team has assigned CVE-2026-72136 to this issue.


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

	Issue introduced in 4.19 with commit f203b76d78092faf248db3f851840fbecf80b40e and fixed in 5.10.261 with commit 04c1aa57d08471b1953bf27c84ac9b3d78d71831
	Issue introduced in 4.19 with commit f203b76d78092faf248db3f851840fbecf80b40e and fixed in 5.15.212 with commit bdfd1c21d90e628a58a9de79e024cdfcbedfa15c
	Issue introduced in 4.19 with commit f203b76d78092faf248db3f851840fbecf80b40e and fixed in 6.1.178 with commit 80ec68bba11f7f387c0e4099c2d7b2c84943eb99
	Issue introduced in 4.19 with commit f203b76d78092faf248db3f851840fbecf80b40e and fixed in 6.6.145 with commit e9c90756f10da334fb31552e52c61f1dba69f491
	Issue introduced in 4.19 with commit f203b76d78092faf248db3f851840fbecf80b40e and fixed in 6.12.97 with commit 37b61946d278c7deb0d40ba8f2b6fc0478d61dab
	Issue introduced in 4.19 with commit f203b76d78092faf248db3f851840fbecf80b40e and fixed in 6.18.40 with commit 8ca2a19a987a7d1cb4c916ed9723a1c6993b4276
	Issue introduced in 4.19 with commit f203b76d78092faf248db3f851840fbecf80b40e and fixed in 7.1.5 with commit 3ba2b2ef7d6a63b190f15cfc2b4ba0fba59928ea
	Issue introduced in 4.19 with commit f203b76d78092faf248db3f851840fbecf80b40e and fixed in 7.2-rc1 with commit 095515d89b19b6cc19dfcdc846f97403ed1ebce3

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-2026-72136
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/xfrm/xfrm_interface_core.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/04c1aa57d08471b1953bf27c84ac9b3d78d71831
	https://git.kernel.org/stable/c/bdfd1c21d90e628a58a9de79e024cdfcbedfa15c
	https://git.kernel.org/stable/c/80ec68bba11f7f387c0e4099c2d7b2c84943eb99
	https://git.kernel.org/stable/c/e9c90756f10da334fb31552e52c61f1dba69f491
	https://git.kernel.org/stable/c/37b61946d278c7deb0d40ba8f2b6fc0478d61dab
	https://git.kernel.org/stable/c/8ca2a19a987a7d1cb4c916ed9723a1c6993b4276
	https://git.kernel.org/stable/c/3ba2b2ef7d6a63b190f15cfc2b4ba0fba59928ea
	https://git.kernel.org/stable/c/095515d89b19b6cc19dfcdc846f97403ed1ebce3