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Vulnerability record · CVE-2020-26210 · published 3 November 2020

CVE-2020-26210: Bookstackapp bookstack cross-site scripting vulnerability

Bookstackapp · Bookstack

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.

8.7 CVSS 3.1 High EPSS 1.2% · top 33.9% CWE-79 · Cross-site scripting
8.7CVSS 3.1 base score, v2 3.5
1.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References, 4 tagged exploit
17 Jun 2026Last modified by NVD

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bookstackapp.com/blog/beta-release-v0-30-4/ ExploitPatchVendor Advisory
https://github.com/BookStackApp/BookStack/commit/349162ea139556b2d25e09e155cec84e21cc9227 PatchThird Party Advisory
https://github.com/BookStackApp/BookStack/releases/tag/v0.30.4 Third Party Advisory
https://github.com/BookStackApp/BookStack/security/advisories/GHSA-7p2j-4h6p-cq3h ExploitThird Party Advisory
https://bookstackapp.com/blog/beta-release-v0-30-4/ ExploitPatchVendor Advisory
https://github.com/BookStackApp/BookStack/commit/349162ea139556b2d25e09e155cec84e21cc9227 PatchThird Party Advisory
https://github.com/BookStackApp/BookStack/releases/tag/v0.30.4 Third Party Advisory
https://github.com/BookStackApp/BookStack/security/advisories/GHSA-7p2j-4h6p-cq3h ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2021-4119Bookstackapp bookstack improper access control vulnerabilitybookstack is vulnerable to Improper Access ControlEPSS 27%8.8CVE-2020-5256Bookstackapp bookstack unrestricted file upload vulnerabilityBookStack before version 0.25.5 has a vulnerability where a user could upload PHP files through image upload functions, which would allow them to exe…EPSS 2.0%8.7CVE-2020-26211Bookstackapp bookstack cross-site scripting vulnerabilityIn BookStack before version 0.30.4, a user with permissions to edit a page could insert JavaScript code through the use of `javascript:` URIs within …EPSS 1.1%6.8CVE-2021-3944Bookstackapp bookstack cross-site request forgery vulnerabilitybookstack is vulnerable to Cross-Site Request Forgery (CSRF)EPSS 0.64%6.5CVE-2023-6199Bookstackapp bookstack server-side request forgery (ssrf) vulnerabilityBook Stack version 23.10.2 allows filtering local files on the server. This is possible because the application is vulnerable to SSRF.EPSS 1.4%6.5CVE-2021-4194Bookstackapp bookstack improper access control vulnerabilitybookstack is vulnerable to Improper Access ControlEPSS 0.71%6.5CVE-2021-3916Bookstackapp bookstack path traversal vulnerabilitybookstack is vulnerable to Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')EPSS 1.2%6.5CVE-2021-3906Bookstackapp bookstack unrestricted file upload vulnerabilitybookstack is vulnerable to Unrestricted Upload of File with Dangerous TypeEPSS 0.67%

Source: NIST National Vulnerability Database (record CVE-2020-26210), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.