{"id":"CVE-2020-5256","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-5256","generatedAt":"2026-10-27T21:19:57.148Z","title":"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.","description":"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.","published":"2020-03-09T16:15:16.000Z","lastModified":"2026-06-17T03:21:09.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-95","CWE-434"],"affected":["bookstackapp/bookstack"],"epss":{"score":0.01969,"percentile":0.80262,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (1.97%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/BookStackApp/BookStack/releases/tag/v0.25.3","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/BookStackApp/BookStack/releases/tag/v0.25.4","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/BookStackApp/BookStack/releases/tag/v0.25.5","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/BookStackApp/BookStack/security/advisories/GHSA-g9rq-x4fj-f5hx","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/BookStackApp/BookStack/releases/tag/v0.25.3","tags":["Release Notes"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/BookStackApp/BookStack/releases/tag/v0.25.4","tags":["Release Notes"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/BookStackApp/BookStack/releases/tag/v0.25.5","tags":["Release Notes"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/BookStackApp/BookStack/security/advisories/GHSA-g9rq-x4fj-f5hx","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-5256","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}