{"id":43871,"date":"2026-04-12T03:14:54","date_gmt":"2026-04-12T03:14:54","guid":{"rendered":"http:\/\/localhost\/?p=43871"},"modified":"2026-04-12T03:14:54","modified_gmt":"2026-04-12T03:14:54","slug":"bookstackapp-bookstack-chapter-export-exportformatterphp-chaptertomarkdown-access-control","status":"publish","type":"post","link":"https:\/\/zero.redgem.net\/?p=43871","title":{"rendered":"BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control_CVE-2026-5484"},"content":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;A weakness has been identified in BookStackApp BookStack up to 26.03. Affected is the function chapterToMarkdown of the file app\/Exports\/ExportFormatter.php of the component Chapter Export Handler. Executing a manipulation of the argument pages can lead to improper access controls. It is possible to launch the attack remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 26.03.1 is able to address this issue. This patch is called 8a59895ba063040cc8dafd82e94024c406df3d04. It is advisable to upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.&#8221;,&#8221;published&#8221;:&#8221;2026-04-03T19:45:12.967Z&#8221;,&#8221;modified&#8221;:&#8221;2026-04-08T18:52:44.563Z&#8221;,&#8221;type&#8221;:&#8221;cve&#8221;,&#8221;title&#8221;:&#8221;BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control&#8221;,&#8221;source&#8221;:&#8221;VulDB&#8221;,&#8221;references&#8221;:&#8221;https:\/\/vuldb.com\/vuln\/355091\\nhttps:\/\/vuldb.com\/vuln\/355091\/cti\\nhttps:\/\/vuldb.com\/submit\/781762\\nhttps:\/\/github.com\/Ghufran2\/CVE-Bookstack\/blob\/main\/Permission%20Bypass%20in%20Markdown%20Chapter%20Export\\nhttps:\/\/www.bookstackapp.com\/blog\/bookstack-release-v26-03-1\/\\nhttps:\/\/github.com\/BookStackApp\/BookStack\/commit\/8a59895ba063040cc8dafd82e94024c406df3d04\\nhttps:\/\/github.com\/BookStackApp\/BookStack\/releases\/tag\/v26.03.1\\nhttps:\/\/github.com\/BookStackApp\/BookStack\/&#8221;,&#8221;id&#8221;:&#8221;CVE-2026-5484&#8243;,&#8221;bulletinFamily&#8221;:&#8221;&#8221;,&#8221;cwe&#8221;:[&#8220;CWE-284&#8243;,&#8221;CWE-266&#8243;],&#8221;cvelist&#8221;:null,&#8221;sourceData&#8221;:&#8221;BookStackApp BookStack 26.03&#8243;,&#8221;sourceHref&#8221;:&#8221;&#8221;,&#8221;cvss&#8221;:{&#8220;score&#8221;:6.9,&#8221;severity&#8221;:&#8221;MEDIUM&#8221;,&#8221;vector&#8221;:&#8221;CVSS:4.0\/AV:N\/AC:L\/AT:N\/PR:N\/UI:N\/VC:L\/VI:N\/VA:N\/SC:N\/SI:N\/SA:N\/E:P&#8221;,&#8221;version&#8221;:&#8221;4.0&#8243;},&#8221;cvss2&#8243;:{},&#8221;cvss3&#8243;:{&#8220;version&#8221;:&#8221;&#8221;,&#8221;vectorString&#8221;:&#8221;&#8221;,&#8221;baseScore&#8221;:0,&#8221;baseSeverity&#8221;:&#8221;&#8221;,&#8221;attackVector&#8221;:&#8221;&#8221;,&#8221;attackComplexity&#8221;:&#8221;&#8221;,&#8221;privilegesRequired&#8221;:&#8221;&#8221;,&#8221;userInteraction&#8221;:&#8221;&#8221;,&#8221;scope&#8221;:&#8221;&#8221;,&#8221;confidentialityImpact&#8221;:&#8221;&#8221;,&#8221;integrityImpact&#8221;:&#8221;&#8221;,&#8221;availabilityImpact&#8221;:&#8221;&#8221;,&#8221;cvssV3&#8243;:{&#8220;version&#8221;:&#8221;&#8221;,&#8221;vectorString&#8221;:&#8221;&#8221;,&#8221;baseScore&#8221;:0,&#8221;baseSeverity&#8221;:&#8221;&#8221;,&#8221;attackVector&#8221;:&#8221;&#8221;,&#8221;attackComplexity&#8221;:&#8221;&#8221;,&#8221;privilegesRequired&#8221;:&#8221;&#8221;,&#8221;userInteraction&#8221;:&#8221;&#8221;,&#8221;scope&#8221;:&#8221;&#8221;,&#8221;confidentialityImpact&#8221;:&#8221;&#8221;,&#8221;integrityImpact&#8221;:&#8221;&#8221;,&#8221;availabilityImpact&#8221;:&#8221;&#8221;}},&#8221;href&#8221;:&#8221;&#8221;,&#8221;category_name&#8221;:&#8221;CVE&#8221;,&#8221;post_link&#8221;:&#8221;&#8221;,&#8221;product&#8221;:&#8221;BookStack&#8221;,&#8221;version&#8221;:&#8221;26.03&#8243;,&#8221;vendor&#8221;:&#8221;BookStackApp&#8221;,&#8221;ai_description&#8221;:&#8221;&#8221;,&#8221;ai_severity&#8221;:&#8221;&#8221;,&#8221;ai_vendor&#8221;:&#8221;&#8221;,&#8221;ai_product&#8221;:&#8221;&#8221;,&#8221;ai_version&#8221;:&#8221;&#8221;,&#8221;ai_score&#8221;:0}<\/p>\n","protected":false},"excerpt":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;A weakness has been identified in BookStackApp BookStack up to 26.03. Affected is the function chapterToMarkdown of the file app\/Exports\/ExportFormatter.php of the component Chapter Export&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[6,8,48,12,21,13,7,11,5],"class_list":["post-43871","post","type-post","status-publish","format-standard","hentry","category-category_cve","tag-cve","tag-cvss","tag-cvss-69","tag-exploit","tag-medium","tag-news","tag-security","tag-tapic","tag-vulnerability"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control_CVE-2026-5484 - zero redgem<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/zero.redgem.net\/?p=43871\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control_CVE-2026-5484 - zero redgem\" \/>\n<meta property=\"og:description\" content=\"{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;A weakness has been identified in BookStackApp BookStack up to 26.03. 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