CVE-2026-72451 xfrm: Fix xfrm state cache insertion race
A race condition in the Linux kernel xfrm state cache allows inserting invalid states, potentially causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72451?
CVE-2026-72451 is a critical vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
xfrm: Fix xfrm state cache insertion race
The xfrm input state cache insertion code checks the validity of the state before acquiring the global xfrm_state_lock. Thus it's possible for someone else to kill the state after it passed the validity check, and then the insertion will add the dead state to the cache.
Fix this by moving the validity check inside the lock.
This entire function is called on the input path, where BH must be off (e.g., the caller of this function xfrm_input acquires its spinlocks without disabling BH).
So there is no need to disable BH here or take the RCU read lock. Remove both and replace them with an assertion that trips if BH is accidentally enabled on some future calling path.
Which versions are affected by CVE-2026-72451?
How do I fix CVE-2026-72451?
Apply the vendor's patch.
Is CVE-2026-72451 being exploited?
There is no known exploitation of CVE-2026-72451 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72451, DEBIAN-CVE-2026-72451, GHSA-pw2h-mp67-xjw4, UBUNTU-CVE-2026-72451.