The vulnerability in nnn arises from a lack of validation on length fields deserialized from session files. When a malicious session file is loaded using the -s option, it can trigger an out-of-bound write beyond fixed-size global buffers, leading to corruption of adjacent global state. This issue was confirmed in version 5.2. The maintainer has been notified but has not specified affected versions or provided a patch. No known exploits are reported in the wild.

An attacker able to place a crafted session file in the victim's nnn session directory can exploit this vulnerability to corrupt adjacent global state in the application. This could lead to unpredictable behavior or potential denial of service. The severity is assessed as low, and no evidence of remote exploitation or privilege escalation is indicated.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or vulnerable version range has been provided by the maintainer, users should avoid loading untrusted session files with the -s option until a fix is available.