CVE-2025-40149 tls: Use __sk_dst_get() and dst_dev_rcu() in get_netdev_for_sock().
A use-after-free vulnerability in the Linux kernel TLS module allows attackers to trigger crashes or potentially execute code via setsockopt calls.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40149?
CVE-2025-40149 is a high-severity use after free vulnerability in Linux kernel, published on 12 Nov 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
tls: Use __sk_dst_get() and dst_dev_rcu() in get_netdev_for_sock().
get_netdev_for_sock() is called during setsockopt(), so not under RCU.
Using sk_dst_get(sk)->dev could trigger UAF.
Let's use __sk_dst_get() and dst_dev_rcu().
Note that the only ->ndo_sk_get_lower_dev() user is bond_sk_get_lower_dev(), which uses RCU.
Weakness: CWE-416
Which versions are affected by CVE-2025-40149?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-40149?
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-2025-40149 being exploited?
There is no known exploitation of CVE-2025-40149 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-70001, AZL-78389, BELL-CVE-2025-40149, DEBIAN-CVE-2025-40149, GHSA-f2w5-mmwp-c76h, ROOT-OS-DEBIAN-11-CVE-2025-40149 and 5 more.