CVE-2026-42451
MediumCVSS 6.3Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
Grimmory, a self-hosted digital library, prior to version 2.3.1 contains a stored cross-site scripting (XSS) vulnerability in its browser-based EPUB reader. This 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.
Risk Assessment
The risk includes session token theft and account takeover, including administrative accounts, which can lead to full compromise of the Grimmory instance.
Recommendation
It is recommended to immediately update Grimmory to version 2.3.1 or later, which contains a fix for this vulnerability.
Original NVD description (English source)
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.