CVE-2026-42451: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in grimmory-tools grimmory
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.
AI Analysis
Technical Summary
CVE-2026-42451 is a stored XSS vulnerability in the Grimmory digital library software's EPUB reader component. The flaw allows attackers to inject arbitrary JavaScript into EPUB files. When these files are opened by users, the script executes in the context of the Grimmory application session, enabling compromise of user sessions and potential account takeover. The vulnerability affects Grimmory versions before 2.3.1 and has been fixed in version 2.3.1.
Potential Impact
Successful exploitation can lead to theft of session tokens and unauthorized account access, including administrative privileges if an administrator opens the malicious EPUB file. This can result in significant compromise of the affected Grimmory instance and its data integrity.
Mitigation Recommendations
Upgrade Grimmory to version 2.3.1 or later, where this vulnerability has been patched. No other mitigations are specified or required once the update is applied.
CVE-2026-42451: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in grimmory-tools grimmory
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.
CVSS v3.1
Score 6.3medium
Affected software
pkg:github/grimmory-tools/grimmoryRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-42451 is a stored XSS vulnerability in the Grimmory digital library software's EPUB reader component. The flaw allows attackers to inject arbitrary JavaScript into EPUB files. When these files are opened by users, the script executes in the context of the Grimmory application session, enabling compromise of user sessions and potential account takeover. The vulnerability affects Grimmory versions before 2.3.1 and has been fixed in version 2.3.1.
Potential Impact
Successful exploitation can lead to theft of session tokens and unauthorized account access, including administrative privileges if an administrator opens the malicious EPUB file. This can result in significant compromise of the affected Grimmory instance and its data integrity.
Mitigation Recommendations
Upgrade Grimmory to version 2.3.1 or later, where this vulnerability has been patched. No other mitigations are specified or required once the update is applied.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-27T13:55:58.693Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69fe6c74cbff5d86103b91bd
Added to database: 05/08/2026, 23:06:28 UTC
Last enriched: 05/16/2026, 10:03:00 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 105
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