What’s Vulnerable › Vulnerabilities

CVE-2021-3915: Unrestricted Upload of File with Dangerous Type in bookstackapp/bookstack

• Severity: medium (CVSS 5.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-11-13 · updated 2026-06-17
• Weakness: CWE-434

Description

bookstack is vulnerable to Unrestricted Upload of File with Dangerous Type

Affected products

• bookstackapp/bookstack: before 21.10.3 — fixed in 21.10.3

How to fix

Upgrade to a fixed version: bookstackapp/bookstack 21.10.3. Check the vendor advisory for mitigations.

References

• https://github.com/bookstackapp/bookstack/commit/ae155d67454d6b9f6c93b2bb457aaa4b2eb1a9ed
• https://huntr.dev/bounties/fcb65f2d-257a-46f4-bac9-f6ded5649079
• https://github.com/bookstackapp/bookstack/commit/ae155d67454d6b9f6c93b2bb457aaa4b2eb1a9ed
• https://huntr.dev/bounties/fcb65f2d-257a-46f4-bac9-f6ded5649079

Get alerted when CVE-2021-3915 or the next vulnerability affects your stack