CVE-2021-3906: Bookstackapp Bookstack

Medium severity, CVSS 6.5. EPSS: 0.7% chance of exploitation in the next 30 days.

bookstack is vulnerable to Unrestricted Upload of File with Dangerous Type

Affected products

• Bookstackapp Bookstack: before 21.10.1 (fixed in 21.10.1)

Published 2021-10-27. Last modified 2026-06-17.