Vulnerability DatabaseCVE-2026-126811
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CVE-2026-126811
Published:November 11, 2026
Updated:November 14, 2026
BookStack before 26.09.3 contains an incorrect authorization vulnerability that allows authenticated users to access other users' unpublished draft page images by checking only PageView permission without draft status. Attackers can read drawio data via the base64 endpoint or rename, replace, or delete draft images by sequential ID to disclose or tamper with unpublished work.
Affected Packages
https://github.com/BookStackApp/BookStack.git (GITHUB):
Affected version(s) >=v0.20.0 <v26.09.3 || >=v21.04 <v26.09.3
Fix Suggestion:
Update to version v26.09.3
Related Resources (12)
https://github.com/fishtankyu/bookstack-draft-image-idor-advisory.md
https://nvd.nist.gov/vuln/detail/CVE-2026-126811
https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.3
https://codeberg.org/bookstack/bookstack/commit/926e16a23f346be47d44746d14cba40cb355cbe1
https://www.bookstackapp.com/blog/bookstack-release-v26-09-3/
https://github.com/BookStackApp/BookStack/commit/926e16a23f346be47d44746d14cba40cb355cbe1
https://codeberg.org/bookstack/bookstack/commit/4fec06236cbfb314fd72c1b3614c7c50162fb41c
https://github.com/BookStackApp/BookStack/releases/tag/v26.09.3
https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/DrawioImageController.php#L82-L92
https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/ImageController.php#L159-L169
https://www.vulncheck.com/advisories/bookstack-before-26.09.3-incorrect-authorization-via-image-and-drawio-endpoints
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126811.json
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CVSS v4
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.4
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Incorrect Authorization
CWE-863
EPSS
Base Score:
0.29