CVE-2025-40074 ipv4: start using dst_dev_rcu()
A use-after-free vulnerability in the Linux kernel IPv4 stack allows attackers to potentially execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40074?
CVE-2025-40074 is a critical use after free vulnerability in Linux, published on 28 Oct 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:
ipv4: start using dst_dev_rcu()
Change icmpv4_xrlim_allow(), ip_defrag() to prevent possible UAF.
Change ipmr_prepare_xmit(), ipmr_queue_fwd_xmit(), ip_mr_output(), ipv4_neigh_lookup() to use lockdep enabled dst_dev_rcu().
Which versions are affected by CVE-2025-40074?
How do I fix CVE-2025-40074?
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-2025-40074 being exploited?
There is no known exploitation of CVE-2025-40074 in the wild and no public exploit code.
Sources
Also known as AZL-68894, BELL-CVE-2025-40074, DEBIAN-CVE-2025-40074, GHSA-g35w-4vfx-hjpg, ROOT-OS-DEBIAN-11-CVE-2025-40074, ROOT-OS-DEBIAN-12-CVE-2025-40074 and 4 more.