CVE-2025-38273 net: tipc: fix refcount warning in tipc_aead_encrypt
A use-after-free vulnerability in the Linux kernel TIPC module can cause a refcount warning and potential system instability during network namespace cleanup.
- 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-2025-38273?
CVE-2025-38273 is a high-severity use after free vulnerability in Debian Debian Linux, published on 10 Jul 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:
net: tipc: fix refcount warning in tipc_aead_encrypt
syzbot reported a refcount warning [1] caused by calling get_net() on a network namespace that is being destroyed (refcount=0). This happens when a TIPC discovery timer fires during network namespace cleanup.
The recently added get_net() call in commit e279024617134 ("net/tipc: fix slab-use-after-free Read in tipc_aead_encrypt_done") attempts to hold a reference to the network namespace. However, if the namespace is already being destroyed, its refcount might be zero, leading to the use-after-free warning.
Replace get_net() with maybe_get_net(), which safely checks if the refcount is non-zero before incrementing it. If the namespace is being destroyed, return -ENODEV early, after releasing the bearer reference.
[1]: https://lore.kernel.org/all/[email protected]/T/#m12019cf9ae77e1954f666914640efa36d52704a2
Which versions are affected by CVE-2025-38273?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-38273?
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-2025-38273 being exploited?
There is no known exploitation of CVE-2025-38273 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2025-38273, DEBIAN-CVE-2025-38273, GHSA-r4r9-4cc8-c2cp, ROOT-OS-DEBIAN-11-CVE-2025-38273, ROOT-OS-DEBIAN-12-CVE-2025-38273, ROOT-OS-UBUNTU-2204-CVE-2025-38273 and 1 more.