A heap-buffer-overflow vulnerability was identified in the ClamAV antivirus software within the cli_strlcat function, as reported by OSS-Fuzz. The issue causes a write overflow on the heap, potentially leading to a crash during YARA rule parsing. No CVSS score or vendor patch information is provided, and no known exploits are reported in the wild. The affected versions include the commit e5f001c9ca4175beecd445004a8e01bbdd29579c and later. The severity is assessed as medium based on the available data.