CVE-2025-40135 ipv6: use RCU in ip6_xmit()
A use-after-free vulnerability in the Linux kernel IPv6 implementation allows attackers to potentially execute code or cause a system crash.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40135?
CVE-2025-40135 is a high-severity use after free vulnerability in Linux, published on 12 Nov 2025. 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:
ipv6: use RCU in ip6_xmit()
Use RCU in ip6_xmit() in order to use dst_dev_rcu() to prevent possible UAF.
Which versions are affected by CVE-2025-40135?
How do I fix CVE-2025-40135?
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-2025-40135 being exploited?
There is no known exploitation of CVE-2025-40135 in the wild and no public exploit code.
Sources
Also known as AZL-69995, BELL-CVE-2025-40135, DEBIAN-CVE-2025-40135, GHSA-q28q-889g-6rx2, ROOT-OS-DEBIAN-11-CVE-2025-40135, ROOT-OS-DEBIAN-12-CVE-2025-40135 and 4 more.