CVE-2026-72136 xfrm: xfrm_interface: require CAP_NET_ADMIN in the device netns for changelink
A local attacker with CAP_NET_ADMIN in one network namespace can modify interfaces in another, leading to privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72136?
CVE-2026-72136 is a high-severity vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-72136?
How do I fix CVE-2026-72136?
Apply the vendor's patch.
Is CVE-2026-72136 being exploited?
There is no known exploitation of CVE-2026-72136 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72136, DEBIAN-CVE-2026-72136, GHSA-87pp-x9f9-85hx, UBUNTU-CVE-2026-72136.