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Vulnerability Details :

CVE-2026-42451

Summary
Assigner-GitHub_M
Assigner Org ID-a0819718-46f1-4df5-94e2-005712e83aaa
Published At-08 May, 2026 | 22:51
Updated At-08 May, 2026 | 22:51
Rejected At-
Credits

Grimmory: Stored XSS via Malicious EPUB Enables Session Token Theft

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.

Vendors
-
Not available
Products
-
Metrics (CVSS)
VersionBase scoreBase severityVector
Weaknesses
Attack Patterns
Solution/Workaround
References
HyperlinkResource Type
EPSS History
Score
Latest Score
-
N/A
No data available for selected date range
Percentile
Latest Percentile
-
N/A
No data available for selected date range
Stakeholder-Specific Vulnerability Categorization (SSVC)
▼Common Vulnerabilities and Exposures (CVE)
cve.org
Assigner:GitHub_M
Assigner Org ID:a0819718-46f1-4df5-94e2-005712e83aaa
Published At:08 May, 2026 | 22:51
Updated At:08 May, 2026 | 22:51
Rejected At:
▼CVE Numbering Authority (CNA)
Grimmory: Stored XSS via Malicious EPUB Enables Session Token Theft

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.

Affected Products
Vendor
grimmory-tools
Product
grimmory
Versions
Affected
  • < 2.3.1
Problem Types
TypeCWE IDDescription
CWECWE-79CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWECWE-80CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
Type: CWE
CWE ID: CWE-79
Description: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Type: CWE
CWE ID: CWE-80
Description: CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
Metrics
VersionBase scoreBase severityVector
3.16.3MEDIUM
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L
Version: 3.1
Base score: 6.3
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions
Configurations
Workarounds
Exploits
Credits
Timeline
EventDate
Replaced By
Rejected Reason
References
HyperlinkResource
https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24
x_refsource_CONFIRM
http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1
x_refsource_MISC
Hyperlink: https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24
Resource:
x_refsource_CONFIRM
Hyperlink: http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1
Resource:
x_refsource_MISC
Information is not available yet
▼National Vulnerability Database (NVD)
nvd.nist.gov
Source:security-advisories@github.com
Published At:08 May, 2026 | 23:16
Updated At:08 May, 2026 | 23:16

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.

CISA Catalog
Date AddedDue DateVulnerability NameRequired Action
N/A
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
TypeVersionBase scoreBase severityVector
Secondary3.16.3MEDIUM
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L
Type: Secondary
Version: 3.1
Base score: 6.3
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L
CPE Matches
Weaknesses
CWE IDTypeSource
CWE-79Primarysecurity-advisories@github.com
CWE-80Primarysecurity-advisories@github.com
CWE ID: CWE-79
Type: Primary
Source: security-advisories@github.com
CWE ID: CWE-80
Type: Primary
Source: security-advisories@github.com
Evaluator Description
Evaluator Impact

Evaluator Solution

Vendor Statements
References
HyperlinkSourceResource
http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1security-advisories@github.com
N/A
https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24security-advisories@github.com
N/A
Hyperlink: http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1
Source: security-advisories@github.com
Resource: N/A
Hyperlink: https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24
Source: security-advisories@github.com
Resource: N/A

Change History

0
Information is not available yet

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