{"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":"2026-09-24T14:20:25.989Z"},"containers":{"cna":{"providerMetadata":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-09-24T14:20:25.989Z"},"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/bookstackapp/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"}}]}}