CVE-2025-4878 Libssh: use of uninitialized variable in privatekey_from_file()
An attacker can trigger heap corruption or signing failures in libssh by providing a non-existent private key file, potentially leading to code execution or denial of service.
- 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-2025-4878?
CVE-2025-4878 is a low-severity use after free vulnerability in Red Hat Enterprise Linux 10, published on 22 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability was found in libssh, where an uninitialized variable exists under certain conditions in the privatekey_from_file() function. This flaw can be triggered if the file specified by the filename doesn't exist and may lead to possible signing failures or heap corruption.
Weakness: CWE-416
Which versions are affected by CVE-2025-4878?
How do I fix CVE-2025-4878?
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-2025-4878 being exploited?
There is no known exploitation of CVE-2025-4878 in the wild and no public exploit code.
Sources
Also known as AZL-65643, AZL-65646, BELL-CVE-2025-4878, DEBIAN-CVE-2025-4878, GHSA-q2fw-m52x-w593, UBUNTU-CVE-2025-4878.