Cisco Warns of High-Severity ClamAV Vulnerabilities Causing Denial-of-Service Conditions

Cisco has disclosed multiple high-severity vulnerabilities in ClamAV that could allow unauthenticated remote attackers to disrupt antivirus scanning operations and cause denial-of-service conditions.

The flaws affect the ClamAV parsers used by Cisco Secure Endpoint Connector on Windows, Linux, and macOS. The advisory was first published on August 7, 2026, and updated on August 10.

Cisco assigned a High security impact rating to affected Windows systems, while Linux and macOS environments received a Medium rating. The company said the difference is due to the privileged security context used by the ClamAV scanning process on Windows devices.