CVE-2023-53745

Vulnerability

The vulnerability is a memory leak in the vector_config function of the Linux kernel's User Mode Linux (UML) networking code. When the uml_parse_vector_ifspec function returns NULL, the memory allocated for params via kzalloc is not freed. This oversight can lead to a gradual depletion of kernel memory.

Exploitation

An attacker with the ability to supply a malformed vector interface specification, such as through a crafted UML configuration, can trigger the NULL return path. No authentication is required if the configuration input is untrusted, and the attack surface is limited to systems using UML networking.

Impact

Successfully exploiting this memory leak can result in denial of service by exhausting available memory. The leak is persistent across repeated trigger attempts, eventually causing system instability or crash.

Mitigation

Patches have been applied to the Linux kernel stable branches, as seen in commit [1]. Users are advised to update to the latest kernel version. The fix adds a kfree(params) call after the NULL check to properly release the allocated memory.