CVE-2025-40075 tcp_metrics: use dst_dev_net_rcu()
A null pointer dereference in the Linux kernel TCP metrics subsystem can cause a system crash, requiring a kernel patch.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40075?
CVE-2025-40075 is a high-severity 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:
tcp_metrics: use dst_dev_net_rcu()
Replace three dst_dev() with a lockdep enabled helper.
Which versions are affected by CVE-2025-40075?
How do I fix CVE-2025-40075?
Apply the vendor's patch.
Is CVE-2025-40075 being exploited?
There is no known exploitation of CVE-2025-40075 in the wild and no public exploit code.
Sources
Also known as AZL-68927, BELL-CVE-2025-40075, DEBIAN-CVE-2025-40075, GHSA-447q-wwcf-54f8, ROOT-OS-DEBIAN-11-CVE-2025-40075, ROOT-OS-DEBIAN-12-CVE-2025-40075 and 4 more.