CVE-2026-42451

MEDIUM EPSS 3.4%

Published May 8, 20261mo ago · Modified Jun 17, 20261w ago

6.3 CVSS 3.1

Medium

Published May 8, 2026 1mo ago

Last Modified Jun 17, 2026 1w ago

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 Details

Base Score

6.3

Exploitability

0.8

Impact

5.5

Vector string

CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L

Attack Vector Local

Attack Complexity High

Privileges Required Low

User Interaction Required

Scope Unchanged

Confidentiality High

Integrity High

Availability Low

Threat Intelligence

EPSS Exploit Probability

3.4% percentile

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 2

CWE-79 Cross-site Scripting Injection

CWE-80

References 2

github.com http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1
github.com https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.