TRN 3.6‑23 suffers from a stack buffer overflow (CWE‑787) that allows an attacker to supply an oversized command‑line argument. The overflow is triggered with 156 bytes of padding followed by a crafted return address, which overwrites the instruction pointer and redirects the program to execute injected shellcode with the same privileges as the user launching TRN. This flaw enables arbitrary code execution at the local user level.

The product affected is Threaded USENET News Reader version 3.6‑23. No other versions or products are currently listed as impacted.

The vulnerability has a CVSS score of 8.6, indicating high severity. No EPSS data is available and the issue is not listed in the CISA KEV catalog, suggesting no publicly documented exploits yet. The attack vector is local; an attacker needs to run TRN with a crafted argument. If local access is granted, a malicious user can trigger the overflow and execute arbitrary code under their own user privileges.