CVE-2020-26211
Cross-Site Scripting in BookStack
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.7
Cross-Site Scripting in BookStack
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.
- Record
CVE-2020-26211- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2022-3579
7.7
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.
- Record
EUVD-2022-3579- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-ch37-ch8w-cfrq
8.7
Bookstack Cross-site Scripting vulnerability
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.
- Record
GHSA-ch37-ch8w-cfrq- CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
7.7
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.
- Record
CVE-2020-26211- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N - CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - CVSS 2.0
- 3.5 Low
AV:N/AC:M/Au:S/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
8.7
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.
- Record
CVE-2020-26211- CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Updated
- 2026-11-02
OSVGHSA-ch37-ch8w-cfrq
8.7
Bookstack Cross-site Scripting vulnerability
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.
- Record
GHSA-ch37-ch8w-cfrq- CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ssddanbrown/bookstackPackagist |
before 0.30.4 | 0.30.4 |
ssddanbrown/bookstackPackagist |
before 0.30.4, plus listed versions 0.7.2V0.7.5v0.10.0v0.11.0v0.11.1 Show 45 moreShow lessv0.11.2v0.12.0v0.12.1v0.12.2v0.13.0v0.13.1v0.14.0v0.14.1v0.14.2v0.14.3v0.15.0v0.15.1v0.15.2v0.15.3v0.16.0v0.16.1v0.16.2v0.16.3v0.17.0v0.17.1v0.17.2v0.17.3v0.17.4v0.18.0v0.18.1v0.18.2v0.18.3v0.18.4v0.18.5v0.19.0v0.20.0v0.20.1v0.20.2v0.20.3v0.21.0v0.22.0v0.23.0v0.23.1v0.23.2v0.24.0v0.24.1v0.24.2v0.24.3v0.25.0v0.25.1 |
0.30.4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-26211 is a high vulnerability (CVSS 7.7) in Bookstackapp Bookstack, published November 3, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.10%, the 65th percentile. Fixed in ssddanbrown/bookstack 0.30.4.
References
github.com/BookStackApp/BookStack/releases/tag/v0.30.4
github.com/BookStackApp/BookStack/security/advisories/GHSA-r2cf-8778-3jgp
github.com/BookStackApp/BookStack/commit/bbd1384acbe7e52c21f89af69f2dc391c95dbf54
bookstackapp.com/blog/beta-release-v0-30-4
nvd.nist.gov/vuln/detail/CVE-2020-26211
github.com/advisories/GHSA-ch37-ch8w-cfrq
github.com/BookStackApp/BookStack
Left out here: 43 versions. The JSON record has them.