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HIGH

CVE-2026-84695

CVSS v3

8.7

HIGH

EPSS Score

0.5 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

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.

Technical details

Published
2026-09-02
Last Modified
2026-09-02

Frequently asked questions

What is CVE-2026-84695?

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.

Is CVE-2026-84695 actively exploited?

Active exploitation of CVE-2026-84695 has not been confirmed. Its EPSS score was 0.5% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-84695?

CVE-2026-84695 has a CVSS v3 base score of 8.7 (HIGH severity).

Is CVE-2026-84695 affecting your environment?

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