CVE-2021-3915

Name: CVE-2021-3915
Creator: NVD / NIST
Published: 2021-11-13T10:15:07.927+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.7/10EPSS 0.93%

Last modified Jun 17, 2026

CVE-2021-3915 is a medium-severity vulnerability rated 5.7/10 on the CVSS scale. bookstack is vulnerable to Unrestricted Upload of File with Dangerous Type. EPSS estimates a 0.93% chance of exploitation in the next 30 days.

Description

bookstack is vulnerable to Unrestricted Upload of File with Dangerous Type

Metrics

CVSS 3.1

5.7/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

EPSS Probability

0.93%

56.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-434

Affected Software

Vendor	Product	Versions
Bookstackapp	Bookstack	< 21.10.3

References

https://github.com/bookstackapp/bookstack/commit/ae155d67454d6b9f6c93b2bb457aaa4b2eb1a9edPatch, Third Party Advisory
https://huntr.dev/bounties/fcb65f2d-257a-46f4-bac9-f6ded5649079Exploit, Patch, Third Party Advisory
https://github.com/bookstackapp/bookstack/commit/ae155d67454d6b9f6c93b2bb457aaa4b2eb1a9edPatch, Third Party Advisory
https://huntr.dev/bounties/fcb65f2d-257a-46f4-bac9-f6ded5649079Exploit, Patch, Third Party Advisory

Timeline

Published: Nov 13, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3915?

bookstack is vulnerable to Unrestricted Upload of File with Dangerous Type

How severe is CVE-2021-3915?

CVE-2021-3915 has a CVSS score of 5.7/10 (MEDIUM severity). The EPSS model estimates a 0.93% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3915?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3915?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST