CVE-2021-43099: Diyhi Bbs

Medium severity, CVSS 4.9. EPSS: 1.1% chance of exploitation in the next 30 days.

An Archive Extraction (AKA "Zip Slip) vulnerability exists in bbs 5.3 in the UpgradeNow function in UpgradeManageAction.java, which unzips the arbitrary upladed zip file without checking filenames. The vulnerability is exploited using a specially crafted archive that holds directory traversal filenames (e.g. ../../evil.exe).

Affected products

• Diyhi Bbs: version 5.3 only

Published 2022-03-28. Last modified 2026-06-17.