CVE-2020-26210

Name: CVE-2020-26210
Creator: NVD / NIST
Published: 2020-11-03T19:15:13.157+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.7/10EPSS 1.16%

Last modified Jun 17, 2026

CVE-2020-26210 is a high-severity vulnerability rated 8.7/10 on the CVSS scale. In BookStack before version 0.30.4, a user with permissions to edit a page could add an attached link which would execute untrusted JavaScript code when clicked by a viewer of the page. Dangerous content may remain in the database after this update. EPSS estimates a 1.16% chance of exploitation in the next 30 days.

Description

In BookStack before version 0.30.4, a user with permissions to edit a page could add an attached link which would execute untrusted JavaScript code when clicked by a viewer of the page. Dangerous content may remain in the database after this update. If you think this could have been exploited the linked advisory provides a SQL query to test. As a workaround, page edit permissions could be limited to only those that are trusted until you can upgrade although this will not address existing exploitation of this vulnerability. The issue is fixed in version 0.30.4.

Metrics

CVSS 3.1

8.7/10

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

EPSS Probability

1.16%

63.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Bookstackapp	Bookstack	< 0.30.4

References

https://bookstackapp.com/blog/beta-release-v0-30-4/Exploit, Patch, Vendor Advisory
https://github.com/BookStackApp/BookStack/commit/349162ea139556b2d25e09e155cec84e21cc9227Patch, Third Party Advisory
https://github.com/BookStackApp/BookStack/releases/tag/v0.30.4Third Party Advisory
https://github.com/BookStackApp/BookStack/security/advisories/GHSA-7p2j-4h6p-cq3hExploit, Third Party Advisory
https://bookstackapp.com/blog/beta-release-v0-30-4/Exploit, Patch, Vendor Advisory
https://github.com/BookStackApp/BookStack/commit/349162ea139556b2d25e09e155cec84e21cc9227Patch, Third Party Advisory
https://github.com/BookStackApp/BookStack/releases/tag/v0.30.4Third Party Advisory
https://github.com/BookStackApp/BookStack/security/advisories/GHSA-7p2j-4h6p-cq3hExploit, Third Party Advisory

Timeline

Published: Nov 3, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26210?

How severe is CVE-2020-26210?

CVE-2020-26210 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 1.16% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26210?

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-2020-26210?

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

Scan your code now

Source: NVD / NIST