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TI-2026-47524 Aliases CVE-2026-67204GHSA-v32j-vgqh-f22g

BookStack < 26.05.4 Broken Access Control via Image Gallery API

Priority LOW 24CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
None · Low · Low
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00413 35th percentileScored 2026-11-07
Fix Fixed BookStack (BookStackApp): 26.05.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
bookstackappBookStackbefore 26.05.426.05.4Patch availableCNA
  • BookStack Vendorbookstackapp Affected before 26.05.4 Fixed in 26.05.4 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:bookstackapp:bookstack:*:*:*:*:*:*:*:*——bookstackapp
  • cpe:2.3:a:bookstackapp:bookstack:*:*:*:*:*:*:*:* Versions — — ·bookstackapp

Remediation

  • Fix · CNA BookStack (BookStackApp) Fixed in 26.05.4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-67204
  2. 2026-10-03 Alias added: GHSA-v32j-vgqh-f22g

References

Advisory 1

Other 2

  • TI-2026-04803 BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control CVSS 4.0MEDIUM 6.9
  • TI-2021-02995 Improper Access Control in bookstackapp/bookstack CVSS 3.1CRITICAL 9.8
  • TI-2023-04263 Server-Side Request Forgery (SSRF) in bookstackapp/bookstack CVSS 3.1LOW 2.4
  • TI-2026-60332 BookStack < 26.05.5 Authentication Bypass via Social Login Provider Confusion CVSS 4.0CRITICAL 9.1
  • TI-2026-56847 BookStack before 26.05.4 Remote Code Execution via Book Cover CVSS 4.0HIGH 8.7
  • TI-2020-04312 Remote Code Execution Through Image Uploads in BookStack CVSS 3.1HIGH 8.8
See all 26 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences