CVE-2020-26211: Bookstack Cross-site Scripting vulnerability
8.7
CVSS Score
3.1
Basic Information
CVE ID
GHSA ID
EPSS Score
0.61833%
CWE
Published
5/24/2022
Updated
7/20/2023
KEV Status
No
Technology
PHP
Technical Details
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
Package Name | Ecosystem | Vulnerable Versions | First Patched Version |
---|---|---|---|
ssddanbrown/bookstack | composer | < 0.30.4 | 0.30.4 |
Vulnerability Intelligence
Miggo AI
Root Cause Analysis
The vulnerability stems from insufficient HTML sanitization in the escapeScripts
method. The GitHub patch adds specific XPath queries to remove dangerous elements (links with javascript:
URIs, forms with javascript:
actions, and redirect meta tags), which were previously not sanitized. The test cases in PageContentTest.php
demonstrate these were exploitable vectors pre-patch. Since escapeScripts
is the primary HTML sanitization function
called during page rendering, its lack of these specific sanitization steps directly enabled the vulnerability.