CVE-2026-31471 xfrm: iptfs: only publish mode_data after clone setup
A use-after-free in the Linux kernel's IPTFS xfrm module allows attackers to cause denial of service or potentially execute code via failed clone operations.
- 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-2026-31471?
CVE-2026-31471 is a high-severity use after free vulnerability in Linux kernel, published on 22 Apr 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: iptfs: only publish mode_data after clone setup
iptfs_clone_state() stores x->mode_data before allocating the reorder window. If that allocation fails, the code frees the cloned state and returns -ENOMEM, leaving x->mode_data pointing at freed memory.
The xfrm clone unwind later runs destroy_state() through x->mode_data, so the failed clone path tears down IPTFS state that clone_state() already freed.
Keep the cloned IPTFS state private until all allocations succeed so failed clones leave x->mode_data unset. The destroy path already handles a NULL mode_data pointer.
Weakness: CWE-415
Which versions are affected by CVE-2026-31471?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31471?
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-2026-31471 being exploited?
There is no known exploitation of CVE-2026-31471 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31471, DEBIAN-CVE-2026-31471, GHSA-xjfc-f2rj-h2hm, UBUNTU-CVE-2026-31471.