{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-42451", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-04-27T13:55:58.693Z", "datePublished": "2026-05-08T22:51:21.920Z", "dateUpdated": "2026-05-08T22:51:21.920Z"}, "containers": {"cna": {"title": "Grimmory: Stored XSS via Malicious EPUB Enables Session Token Theft", "problemTypes": [{"descriptions": [{"cweId": "CWE-79", "lang": "en", "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-80", "lang": "en", "description": "CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "LOW", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L", "version": "3.1"}}], "references": [{"name": "https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24"}, {"name": "http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1", "tags": ["x_refsource_MISC"], "url": "http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1"}], "affected": [{"vendor": "grimmory-tools", "product": "grimmory", "versions": [{"version": "< 2.3.1", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-05-08T22:51:21.920Z"}, "descriptions": [{"lang": "en", "value": "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."}], "source": {"advisory": "GHSA-frv6-5wq5-9p24", "discovery": "UNKNOWN"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-42451", "lastModified": "2026-05-08T23:16:38.680", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "LOW", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L", "version": "3.1"}, "exploitabilityScore": 0.8, "impactScore": 5.5, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-05-08T23:16:38.680", "references": [{"source": "security-advisories@github.com", "url": "http://github.com/grimmory-tools/grimmory/releases/tag/v2.3.1"}, {"source": "security-advisories@github.com", "url": "https://github.com/grimmory-tools/grimmory/security/advisories/GHSA-frv6-5wq5-9p24"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-79"}, {"lang": "en", "value": "CWE-80"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"created": "2026-05-09T00:30:21.261607+00:00", "updated": "2026-05-09T00:30:21.261619+00:00", "vendors": []}