CVE-2026-42451

Medium

Description

Grimmory is a self-hosted digital library. Prior to version 2.3.1, a stored cross-site scripting (XSS) vulnerability in Grimmory's browser-based EPUB reader allows an attacker to embed arbitrary JavaScript in a crafted EPUB file. When a victim opens the book, the script executes in their browser with full access to the Grimmory application's session context. This can enable session token theft and account takeover, including administrative access if an administrator opens the affected book. This issue has been patched in version 2.3.1.

SeverityMedium
CVSS6.3
Exploit probability—
ProductGrimmory
PublishedMay 8, 2026
First seenMay 8, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
grimmory-tools grimmory< 2.3.1—

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CVE-2026-42451 · Grimmory · Dark Radar