CVE-2025-4134: Avast Business Antivirus

High severity, CVSS 7.3. EPSS: 0.2% chance of exploitation in the next 30 days.

Lack of file validation in do_update_vps in Avast Business Antivirus for Linux 4.5 on Linux allows local user to spoof or tamper with the update file via an unverified file write.

Affected products

• Avast Avast Business Antivirus: version 4.5.1 only

Published 2025-05-28. Last modified 2026-06-17.