EUVD-2026-267762

fkie_cve-2026-25889

File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, preview, rename and edit files. Prior to 2.57.1, a case-sensitivity flaw in the password validation logic allows any authenticated user to change their password (or an admin to change any user's password) without providing the current password. By using Title Case field name "Password" instead of lowercase "password" in the API request, the current_password verification is completely bypassed. This enables account takeover if an attacker obtains a valid JWT token through XSS, session hijacking, or other means. This vulnerability is fixed in 2.57.1.

GHSA-hxw8-4h9j-hq2r — File Browser has an Authentication Bypass in User Password Update

Affected: Go: github.com/filebrowser/filebrowser/v2

# Security Advisory: Authentication Bypass in User Password Update

## Summary

A case-sensitivity flaw in the password validation logic allows any authenticated user to change their password (or an admin to change any user's password) **without providing the current password**. By using Title Case field name `"Password"` instead of lowercase `"password"` in the API request, the `current_password` verification is completely bypassed. This enables account takeover if an attacker obtains a valid JWT token through XSS, session hijacking, or other means.

**CVSS Score**: 7.5 (High) **CWE**: CWE-178 (Improper Handling of Case Sensitivity)

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## Details

The vulnerability exists in `http/users.go` in the `userPutHandler` function (lines 181-200).

### Vulnerable Code

```go // http/users.go:181-200 if d.settings.AuthMethod == auth.MethodJSONAuth { var sensibleFields = map[string]struct{}{ "all": {}, "username": {}, "password": {}, // lowercase "scope": {}, "lockPassword": {}, "commands": {}, "perm": {}, }

for _, field := range req.Which { if _, ok := sensibleFields[field]; ok { // Case-sensitive lookup if !users.CheckPwd(req.CurrentPassword, d.user.Password) { return http.StatusBadRequest, fberrors.ErrCurrentPasswordIncorrect } break } } } ```

### Root Cause

1. The `sensibleFields` map uses **lower…

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EUVD-2026-267762

fkie_cve-2026-25889

GHSA-hxw8-4h9j-hq2r — File Browser has an Authentication Bypass in User Password Update