CVE-2026-82450

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-82450", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-08-29T13:22:57.885Z", "datePublished": "2026-08-29T13:47:53.312Z", "dateUpdated": "2026-10-08T15:51:45.531Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-10-08T15:51:45.531Z"}, "datePublic": "2026-08-22T00:00:00.000Z", "title": "BookStack before 26.05.4 Remote Code Execution via Book Cover", "descriptions": [{"lang": "en", "value": "BookStack before 26.05.4 contains a remote code execution vulnerability in the portable ZIP import functionality that allows users with Import Content and Create Books permissions to upload a PHP polyglot file as a book cover. Attackers can bypass image extension validation by embedding a PHP file with a .php filename in the ZIP archive, which is stored in the public web root and executed by unauthenticated requests."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Unrestricted Upload of File with Dangerous Type", "cweId": "CWE-434", "type": "CWE"}]}], "affected": [{"vendor": "bookstackapp", "product": "bookstack", "defaultStatus": "unaffected", "packageURL": "pkg:composer/ssddanbrown/bookstack", "versions": [{"version": "0", "lessThan": "26.05.4", "status": "affected", "versionType": "custom"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:bookstackapp:bookstack:*:*:*:*:*:*:*:*", "versionEndExcluding": "26.05.4"}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 8.7, "baseSeverity": "HIGH"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH"}}], "references": [{"url": "https://github.com/BookStackApp/BookStack/commit/e210cc32e4cbb1efeae5c5c9d0fef8e3c6a752e6", "tags": ["patch"], "name": "Patch Commit"}, {"url": "https://github.com/BookStackApp/BookStack", "tags": ["product"]}, {"name": "VulnCheck Advisory: BookStack before 26.05.4 Remote Code Execution via Book Cover", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/bookstack-before-26.05.4-remote-code-execution-via-book-cover"}], "credits": [{"lang": "en", "value": "Submersion.ai Security Research Team", "type": "finder"}], "x_generator": {"engine": "vulncheck-endgame"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-08-31T18:21:11.099545Z", "id": "CVE-2026-82450", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-08-31T18:21:21.212Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-82450", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-08-31T18:21:11.099545Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-08-31T18:21:17.579Z"}}], "cna": {"title": "BookStack before 26.05.4 Remote Code Execution via Book Cover", "credits": [{"lang": "en", "type": "finder", "value": "Submersion.ai Security Research Team"}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "baseScore": 8.7, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH"}}, {"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.8, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}}], "affected": [{"vendor": "bookstackapp", "product": "bookstack", "versions": [{"status": "affected", "version": "0", "lessThan": "26.05.4", "versionType": "custom"}], "packageURL": "pkg:composer/bookstackapp/bookstack", "defaultStatus": "unaffected"}], "datePublic": "2026-08-22T00:00:00.000Z", "references": [{"url": "https://github.com/BookStackApp/BookStack/commit/e210cc32e4cbb1efeae5c5c9d0fef8e3c6a752e6", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://github.com/BookStackApp/BookStack", "tags": ["product"]}, {"url": "https://www.vulncheck.com/advisories/bookstack-before-26.05.4-remote-code-execution-via-book-cover", "name": "VulnCheck Advisory: BookStack before 26.05.4 Remote Code Execution via Book Cover", "tags": ["third-party-advisory"]}], "x_generator": {"engine": "vulncheck-endgame"}, "descriptions": [{"lang": "en", "value": "BookStack before 26.05.4 contains a remote code execution vulnerability in the portable ZIP import functionality that allows users with Import Content and Create Books permissions to upload a PHP polyglot file as a book cover. Attackers can bypass image extension validation by embedding a PHP file with a .php filename in the ZIP archive, which is stored in the public web root and executed by unauthenticated requests."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-434", "description": "Unrestricted Upload of File with Dangerous Type"}]}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:bookstackapp:bookstack:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "26.05.4"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-09-24T14:20:25.989Z"}}}, "cveMetadata": {"cveId": "CVE-2026-82450", "state": "PUBLISHED", "dateUpdated": "2026-09-24T14:20:25.989Z", "dateReserved": "2026-08-29T13:22:57.885Z", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "datePublished": "2026-08-29T13:47:53.312Z", "assignerShortName": "VulnCheck"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "packageURL": "pkg:composer/ssddanbrown/bookstack", "product": "bookstack", "vendor": "bookstackapp", "versions": [{"lessThan": "26.05.4", "status": "affected", "version": "0", "versionType": "custom"}]}], "source": "disclosure@vulncheck.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "BookStack before 26.05.4 contains a remote code execution vulnerability in the portable ZIP import functionality that allows users with Import Content and Create Books permissions to upload a PHP polyglot file as a book cover. Attackers can bypass image extension validation by embedding a PHP file with a .php filename in the ZIP archive, which is stored in the public web root and executed by unauthenticated requests."}], "id": "CVE-2026-82450", "lastModified": "2026-10-08T16:17:49.150", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-82450", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-08-31T18:21:11.099545Z", "version": "2.0.3"}}]}, "published": "2026-08-29T14:16:37.930", "references": [{"source": "disclosure@vulncheck.com", "url": "https://github.com/BookStackApp/BookStack"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/BookStackApp/BookStack/commit/e210cc32e4cbb1efeae5c5c9d0fef8e3c6a752e6"}, {"source": "disclosure@vulncheck.com", "url": "https://www.vulncheck.com/advisories/bookstack-before-26.05.4-remote-code-execution-via-book-cover"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-434"}], "source": "disclosure@vulncheck.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,26.05.4)"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "bookstack", "source": "cna", "vendor": "bookstackapp"}, "product": "bookstack", "vendor": "bookstackapp"}], "created": "2026-08-29T15:30:04.814737+00:00", "updated": "2026-08-29T16:00:03.551164+00:00", "vendors": ["bookstackapp", "bookstackapp$PRODUCT$bookstack"]}