CVE-2005-3381: Ukranian National Antivirus Una

Medium severity, CVSS 5.0. EPSS: 2.1% chance of exploitation in the next 30 days.

Multiple interpretation error in Ukrainian National Antivirus (UNA) 1.83.2.16 with kernel 265 allows remote attackers to bypass virus scanning via a file such as BAT, HTML, and EML with an "MZ" magic byte sequence which is normally associated with EXE, which causes the file to be treated as a safe type that could still be executed as a dangerous file type by applications on the end system, as demonstrated by a "triple headed" program that contains EXE, EML, and HTML content, aka the "magic byte bug."

Affected products

Published 2005-10-30. Last modified 2026-06-16.