XSS in Bookstackapp Bookstack
CVE-2020-26211
In 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 a link or form which would run, within the context of the current page, when clicked or submitted. Additionally, a user with permissions to edit a page could insert a particular meta tag which could be used to silently redirect users to a alternative location upon visit of a page. Dangerous content may remain in the database but will be removed before being displayed on a page. If you think this could have been exploited the linked advisory provides a SQL query to test. As a workaround without upgrading, 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 BookStack version 0.30.4.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.011 (61.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N.
Affected products
- Bookstackapp Bookstack — versions < 0.30.4
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (Third Party Advisory, x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC, Vendor Advisory)
Frequently asked questions
- What is CVE-2020-26211?
- CVE-2020-26211 is a high-severity vulnerability in Bookstackapp Bookstack, classified under Cross-site Scripting. CVSS score: 7.7/10. Published 2020-11-03.
- How severe is CVE-2020-26211?
- High severity. CVSS v3 base score is 7.7 out of 10.
- Is CVE-2020-26211 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.