{"id":"CVE-2026-23849","aliases":["GHSA-43mm-m3h2-3prc","GO-2026-4344"],"url":"https://o3.security/vulnerability/CVE-2026-23849","summary":"File Browser vulnerable to Username Enumeration via Timing Attack in /api/login","details":"File Browser provides a file managing interface within a specified directory and can be used to upload, delete, preview, rename, and edit files. Prior to version 2.55.0, the JSONAuth. Auth function contains a logic flaw that allows unauthenticated attackers to enumerate valid usernames by measuring the response time of the /api/login endpoint. The vulnerability exists due to a \"short-circuit\" evaluation in the authentication logic. When a username is not found in the database, the function returns immediately. However, if the username does exist, the code proceeds to verify the password using bcrypt (users.CheckPwd), which is a computationally expensive operation designed to be slow. This difference in execution path creates a measurable timing discrepancy. Version 2.55.0 contains a patch for the issue.","published":"2026-01-19T20:37:29.716Z","modified":"2026-08-07T11:50:30.754330112Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/filebrowser/filebrowser","fixedVersion":null},{"ecosystem":"Go","name":"github.com/filebrowser/filebrowser/v2","fixedVersion":"2.55.0"}],"fix":{"url":"https://github.com/filebrowser/filebrowser/commit/24781badd413ee20333aba5cce1919d676e01889","label":"filebrowser/filebrowser@24781ba"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23849.json"},{"type":"ADVISORY","url":"https://github.com/filebrowser/filebrowser/security/advisories/GHSA-43mm-m3h2-3prc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23849"},{"type":"FIX","url":"https://github.com/filebrowser/filebrowser/commit/24781badd413ee20333aba5cce1919d676e01889"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:50:30.754330112Z"}}