CVE-2025-68188 tcp: use dst_dev_rcu() in tcp_fastopen_active_disable_ofo_check()
A use-after-free vulnerability in the Linux kernel TCP stack allows remote attackers to cause denial of service or potentially execute code via crafted packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68188?
CVE-2025-68188 is an use after free vulnerability in Linux, published on 16 Dec 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:
tcp: use dst_dev_rcu() in tcp_fastopen_active_disable_ofo_check()
Use RCU to avoid a pair of atomic operations and a potential UAF on dst_dev()->flags.
Which versions are affected by CVE-2025-68188?
How do I fix CVE-2025-68188?
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-2025-68188 being exploited?
There is no known exploitation of CVE-2025-68188 in the wild and no public exploit code.
Sources
Also known as AZL-72538, BELL-CVE-2025-68188, DEBIAN-CVE-2025-68188, GHSA-3mc8-x7c9-wfw9, ROOT-OS-DEBIAN-11-CVE-2025-68188, ROOT-OS-DEBIAN-12-CVE-2025-68188 and 4 more.