Hashcat’s fgetl() function writes a null terminator one byte beyond the supplied buffer when the length of an input line exactly equals HCBUFSIZ_LARGE characters. This off‑by‑one out‑of‑bounds heap write can corrupt adjacent heap memory and, if an attacker supplies a crafted hash file, potfile, or wordlist containing such a line, may cause the program to crash or corrupt data used later by the application.

Vendor hashcat, the open‑source password‑cracking utility hashcat, is affected in version 7.1.2 and earlier. Any installation built from the source code before the corrective commit 93b55d37d3b2340013d4036f10181ddc67d44249 is vulnerable.

The CVSS score of 6.9 indicates moderate severity. EPSS is not available and the vulnerability is not listed in the CISA KEV catalog, suggesting no publicly known exploit. The attack vector is local: an adversary who controls a file provided to hashcat can trigger the heap write. Because the flaw involves unchecked heap boundaries, a skilled attacker might achieve local denial of service or, in the worst case, local code execution, but no remote or privilege‑escalation attacks are documented.