# CVE-2026-125870: BookStack before 26.09.3 Broken Access Control via ImageController

Status: published. Published: 2026-11-12. Updated: 2026-11-12.

BookStack before 26.09.3 contains a missing authorization vulnerability in ImageController::checkImagePermission() that allows authenticated non-admin users to bypass page-level content restrictions for images whose owning page has been moved to the recycle bin, because the permission check relies on Page::getPage() which returns null for soft-deleted pages and silently skips the PageView check. Attackers can enumerate sequential image IDs via GET /images/edit/{id} to disclose metadata of restricted images, and users with image-update-all/image-delete-all privileges can rename, replace, or permanently delete images belonging to content they cannot view, persisting the damage even after the page is restored.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.3
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/BookStackApp/BookStack/releases/tag/v26.09.3

## Affected products and versions

- bookstackapp / bookstack (bookstackapp/bookstack): ≥ 0; < 26.09.3 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 2.3 (low); CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 4.2 (medium); CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-863

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.3 (CNA: VulnCheck; patch)

- https://github.com/BookStackApp/BookStack/releases/tag/v26.09.3 (CNA: VulnCheck; patch)

- https://www.bookstackapp.com/blog/bookstack-release-v26-09-3/ (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/bookstack-before-broken-access-control-via-imagecontroller (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-125870; retrieved 2026-11-12; source updated 2026-11-12

Revision: 79532884168ad8bd25295ac11840ddff140e242abd963427a1a97a453d9a22cb

Canonical: https://y2.dev/cve/CVE-2026-125870

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