CVE-2020-5256: high-severity vulnerability in BookStackApp BookStack
Remote Code Execution Through Image Uploads in BookStack
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.9epss 2.0%
BookStack before version 0.25.5 has a vulnerability where a user could upload PHP files through image upload functions, which would allow them to execute code on the host system remotely. They would then have the permissions of the PHP process. This most impacts scenarios where non-trusted users are given permission to upload images in any area of the application. The issue was addressed in a series of patches in versions 0.25.3, 0.25.4 and 0.25.5. Users should upgrade to at least v0.25.5 to avoid this vulnerability.
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L
Affected products
BookStackApp · BookStackRelated CVEs — BookStackApp BookStack
In the same product, most dangerous first.
CVE-2020-26210HIGHCross-Site Scripting in BookStackEPSS 1.2%CVE-2020-26211HIGHCross-Site Scripting in BookStackEPSS 1.1%CVE-2020-26260MEDIUMServer Side Request Forgery in BookStackEPSS 0.8%CVE-2020-11055MEDIUMCross-site Scripting in BookStackEPSS 0.8%CVE-2026-67204MEDIUMBookStack < 26.05.4 Broken Access Control via Image Gallery APIEPSS 0.4%CVE-2026-5484MEDIUMBookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access controlEPSS 0.3%