TI-2026-58223 Aliases CVE-2026-84695 GHSA-r46q-wv4x-rj72

BookStack before 26.05.4 Stored XSS via Drawing Upload

MEDIUM 40CWE-79Published 2026-09-02 · Updated 2026-09-02

Key facts

Attack vector: Network
Privileges required: Low
User interaction: Passive
Attack complexity: Low
Attack requirements: None
Impact type: Cross-site scripting
Confidentiality · integrity · availability: High · High · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

BookStack before 26.05.4 contains a stored cross-site scripting vulnerability in the drawing upload endpoint that accepts unvalidated base64 content and stores it without content inspection. Attackers with editor permissions can upload SVG files containing scripts that execute in administrator browsers when accessed through the image gallery API without content-type validation or CSP headers.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0047 40th 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

Vendor	Product	Affected versions	Fixed in	Status	Source
bookstackapp	bookstack	before 26.05.4	26.05.4	Patch available	CNA

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.

CPE	Versions	Role	Vendor
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

2026-10-02 Threatist record created from CVE-2026-84695
2026-10-03 Alias added: GHSA-r46q-wv4x-rj72

References

Patch 1

Patch Commit

Advisory 1

https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/

Other 3

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