{"id":"CVE-2026-82450","revision":"abe0337e5fa84e568162ffc39c123a29","records":[{"revision":"abe0337e5fa84e568162ffc39c123a29","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-82450","aliases":[],"title":"BookStack before 26.05.4 Remote Code Execution via Book Cover","description":"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.","state":0,"publishedAt":"2026-08-29T13:47:53.312+00:00","modifiedAt":"2026-10-08T15:51:45.531+00:00","affected":[{"ecosystem":"Vendor product","name":"bookstack","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"bookstackapp\",\n                    \"product\": \"bookstack\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"packageURL\": \"pkg:composer/ssddanbrown/bookstack\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"26.05.4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"custom\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"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","score":8.7,"severity":"HIGH"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8,"severity":"HIGH"}],"references":["https://github.com/BookStackApp/BookStack/commit/e210cc32e4cbb1efeae5c5c9d0fef8e3c6a752e6","https://github.com/BookStackApp/BookStack","https://www.vulncheck.com/advisories/bookstack-before-26.05.4-remote-code-execution-via-book-cover"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-82450","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-82450","identifiers":["CVE-2026-82450"]},"retained":false,"historicalAffected":[]}],"coverage":[]}