{"affected":[{"defaultStatus":"unaffected","ecosystem":"github","packageName":"BookStackApp/BookStack","product":"BookStack","source":"CNA: VulnCheck","vendor":"BookStackApp","versions":[{"lessThan":"26.09.3","status":"affected","version":"0","versionType":"custom"}]}],"cveId":"CVE-2026-126811","cwes":["CWE-863"],"description":"BookStack before 26.09.3 contains an incorrect authorization vulnerability that allows authenticated users to access other users' unpublished draft page images by checking only PageView permission without draft status. Attackers can read drawio data via the base64 endpoint or rename, replace, or delete draft images by sequential ID to disclose or tamper with unpublished work.","epss":{"date":"2026-11-12","percentile":0.2173,"score":0.00289},"exploits":[],"kev":null,"metrics":[{"score":5.3,"severity":"medium","source":"CNA: VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"},{"score":5.4,"severity":"medium","source":"CNA: VulnCheck","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","version":"3.1"},{"score":5.3,"severity":"medium","source":"NVD: disclosure@vulncheck.com","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/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"},{"score":5.4,"severity":"medium","source":"NVD: disclosure@vulncheck.com","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","version":"3.1"}],"modifiedAt":1794506112075,"publishedAt":1794430392349,"references":[{"source":"CNA: VulnCheck","tags":["patch"],"url":"https://codeberg.org/bookstack/bookstack/commit/926e16a23f346be47d44746d14cba40cb355cbe1"},{"source":"CNA: VulnCheck","tags":["patch"],"url":"https://codeberg.org/bookstack/bookstack/commit/4fec06236cbfb314fd72c1b3614c7c50162fb41c"},{"source":"CNA: VulnCheck","tags":["patch"],"url":"https://github.com/BookStackApp/BookStack/commit/926e16a23f346be47d44746d14cba40cb355cbe1"},{"source":"CNA: VulnCheck","tags":["release-notes"],"url":"https://www.bookstackapp.com/blog/bookstack-release-v26-09-3/"},{"source":"CNA: VulnCheck","tags":["release-notes"],"url":"https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.3"},{"source":"CNA: VulnCheck","tags":["release-notes"],"url":"https://github.com/BookStackApp/BookStack/releases/tag/v26.09.3"},{"source":"CNA: VulnCheck","tags":["technical-description"],"url":"https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/DrawioImageController.php#L82-L92"},{"source":"CNA: VulnCheck","tags":["technical-description"],"url":"https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/ImageController.php#L159-L169"},{"source":"CNA: VulnCheck","tags":["third-party-advisory"],"url":"https://github.com/fishtankyu/bookstack-draft-image-idor-advisory.md"},{"source":"CNA: VulnCheck","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/bookstack-before-26.09.3-incorrect-authorization-via-image-and-drawio-endpoints"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://codeberg.org/bookstack/bookstack/commit/4fec06236cbfb314fd72c1b3614c7c50162fb41c"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://codeberg.org/bookstack/bookstack/commit/926e16a23f346be47d44746d14cba40cb355cbe1"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.3"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/DrawioImageController.php#L82-L92"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://github.com/BookStackApp/BookStack/blob/v26.09.2/app/Uploads/Controllers/ImageController.php#L159-L169"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://github.com/BookStackApp/BookStack/commit/926e16a23f346be47d44746d14cba40cb355cbe1"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://github.com/BookStackApp/BookStack/releases/tag/v26.09.3"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://github.com/fishtankyu/bookstack-draft-image-idor-advisory.md"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://www.bookstackapp.com/blog/bookstack-release-v26-09-3/"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://www.vulncheck.com/advisories/bookstack-before-26.09.3-incorrect-authorization-via-image-and-drawio-endpoints"}],"remediation":[{"kind":"fix","source":"CNA: VulnCheck","text":"The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.","url":"https://codeberg.org/bookstack/bookstack/commit/926e16a23f346be47d44746d14cba40cb355cbe1"},{"kind":"fix","source":"CNA: VulnCheck","text":"The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.","url":"https://codeberg.org/bookstack/bookstack/commit/4fec06236cbfb314fd72c1b3614c7c50162fb41c"},{"kind":"fix","source":"CNA: VulnCheck","text":"The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.","url":"https://github.com/BookStackApp/BookStack/commit/926e16a23f346be47d44746d14cba40cb355cbe1"}],"revision":"efe014e15b150386ab274af9472edcf88cf536e73711abc3b4c76fb7da9dcec7","sources":[{"modifiedAt":1794506112075,"name":"CNA: VulnCheck","retrievedAt":1794507028329,"url":"https://www.cve.org/CVERecord?id=CVE-2026-126811"},{"modifiedAt":1794431805507,"name":"NVD","retrievedAt":1794443547188,"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-126811"},{"modifiedAt":null,"name":"FIRST EPSS","retrievedAt":1794507042103,"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-126811"}],"ssvc":{"assessedAt":1794500848270,"automatable":"no","exploitation":"none","source":"ADP: CISA-ADP","technicalImpact":"partial"},"status":"published","title":"BookStack before 26.09.3 Incorrect Authorization via Image and Drawio Endpoints","updatedAt":1794507042103}