CVE-2026-126811
BookStack before 26.09.3 Incorrect Authorization via Image and Drawio Endpoints
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before 26.09.3 contains an incorrect authorization vulnerability that allows authenticated users to access other users' unpublished draft page images by checking only PageView permission without draft status.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data via the base64 endpoint or rename, replace, or delete draft images by sequential ID to disclose or tamper with unpublished work.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| BookStack BookStackApp BookStackApp/BookStack
github |
≥ 0; < 26.09.3 (affected, custom)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 5.3 medium |
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 5.4 medium |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N | CNA: VulnCheck |
| 4.0 / 5.3 medium |
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD: [email protected] |
| 3.1 / 5.4 medium |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://codeberg.org/bookstack/bookstack/commit/926e16a23f346be47d44746d14cba40cb355cbe1CNA: VulnCheck · patch
- https://codeberg.org/bookstack/bookstack/commit/4fec06236cbfb314fd72c1b3614c7c50162fb41cCNA: VulnCheck · patch
- https://github.com/BookStackApp/BookStack/commit/926e16a23f346be47d44746d14cba40cb355cbe1CNA: VulnCheck · patch
- https://www.bookstackapp.com/blog/bookstack-release-v26-09-3/CNA: VulnCheck · release-notes
- https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.3CNA: VulnCheck · release-notes
- https://github.com/BookStackApp/BookStack/releases/tag/v26.09.3CNA: VulnCheck · release-notes
- https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/DrawioImageController.php#L82-L92CNA: VulnCheck · technical-description
- https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/ImageController.php#L159-L169CNA: VulnCheck · technical-description
- https://github.com/fishtankyu/bookstack-draft-image-idor-advisory.mdCNA: VulnCheck · third-party-advisory
- https://www.vulncheck.com/advisories/bookstack-before-26.09.3-incorrect-authorization-via-image-and-drawio-endpointsCNA: VulnCheck · third-party-advisory
- https://codeberg.org/bookstack/bookstack/commit/4fec06236cbfb314fd72c1b3614c7c50162fb41c[email protected]
- https://codeberg.org/bookstack/bookstack/commit/926e16a23f346be47d44746d14cba40cb355cbe1[email protected]
- https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.3[email protected]
- https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/DrawioImageController.php#L82-L92[email protected]
- https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/ImageController.php#L159-L169[email protected]
- https://github.com/BookStackApp/BookStack/commit/926e16a23f346be47d44746d14cba40cb355cbe1[email protected]
- https://github.com/BookStackApp/BookStack/releases/tag/v26.09.3[email protected]
- https://github.com/fishtankyu/bookstack-draft-image-idor-advisory.md[email protected]
- https://www.bookstackapp.com/blog/bookstack-release-v26-09-3/[email protected]
- https://www.vulncheck.com/advisories/bookstack-before-26.09.3-incorrect-authorization-via-image-and-drawio-endpoints[email protected]
For agents and automation
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