Medium 5.4Published Aug 24, 2026

CVE-2026-67204BookStack < 26.05.4 Broken Access Control via Image Gallery API

Updated under an hour ago (2026-10-19 09:10 UTC)

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It affects BookStackApp BookStack. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for BookStackApp BookStack

Exploited in the last 30 days

BookStack before 26.05.4 contains a broken access control vulnerability that allows authenticated API users with image-update or image-delete permissions to manipulate other users' avatars by exploiting missing content-type restrictions in the Image Gallery API endpoints. Attackers can supply a user avatar's ID to the API controller, which loads any image type without the web controller's gallery and drawio restrictions, and when the avatar's uploaded_to field matches a page ID accessible to the attacker, the authorization check passes allowing the attacker to rename, replace, or delete the target user's avatar without requiring user-management permission.

CVSS: 5.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
Weakness (CWE): CWE-863
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Oct 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

BookStackApp BookStack bookstackapp:bookstack (from the name)	before 26.05.4	CNA record

References

https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/vendor-advisory
https://codeberg.org/bookstack/bookstack/releases/tag/v26.05.4release-notes
https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4release-notes
https://www.vulncheck.com/advisories/bookstack-broken-access-control-via-image-gallery-apithird-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.