File Browser vulnerable to Username Enumeration via Timing Attack in /api/login_CVE-2026-23849

{
    "lastseen": "",
    "description": "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": "2026-01-19T20:37:29.716Z",
    "type": "cve",
    "title": "File Browser vulnerable to Username Enumeration via Timing Attack in /api/login",
    "source": "GitHub_M",
    "references": "https://github.com/filebrowser/filebrowser/security/advisories/GHSA-43mm-m3h2-3prc\nhttps://github.com/filebrowser/filebrowser/commit/24781badd413ee20333aba5cce1919d676e01889",
    "id": "CVE-2026-23849",
    "bulletinFamily": "",
    "cwe": [
        "CWE-208"
    ],
    "cvelist": null,
    "sourceData": "filebrowser filebrowser < 2.55.0",
    "sourceHref": "",
    "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",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "filebrowser",
    "version": "< 2.55.0",
    "vendor": "filebrowser",
    "ai_description": "",
    "ai_severity": "",
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    "ai_product": "",
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    "ai_score": 0
}