Advisories for Golang/Github.com/Filebrowser/Filebrowser/V2 package

The fix in commit b6a4fb1 ("self-registered users don't get execute perms") stripped Execute permission and Commands from users created via the signup handler. The same fix was not applied to the proxy auth handler. Users auto-created on first successful proxy-auth login are granted execution capabilities from global defaults, even though the signup path was explicitly changed to prevent execution rights from being inherited by automatically provisioned accounts. Confirmed on v2.62.2 …

When an admin revokes a user's Share and Download permissions, existing share links created by that user remain fully accessible to unauthenticated users. The public share download handler does not re-check the share owner's current permissions. Verified with a running PoC against v2.62.2 (commit 860c19d).

Hi, The Matches() function in rules/rules.go uses strings.HasPrefix() without a trailing directory separator when matching paths against access rules. A rule for /uploads also matches /uploads_backup/, granting or denying access to unintended directories. Verified against v2.62.2 (commit 860c19d).

[!NOTE] This feature has been disabled by default for all installations from v2.33.8 onwards, including for existent installations. To exploit this vulnerability, the instance administrator must turn on a feature and ignore all the warnings about known vulnerabilities. We're publishing this new advisory to make it clear that it also applies to Hook Runners and not just to the Shell Commands, since all advisories until now focused only on the …

The resourceGetHandler in http/resource.go returns full text file content without checking the Perm.Download permission flag. All three other content-serving endpoints (/api/raw, /api/preview, /api/subtitle) correctly verify this permission before serving content. A user with download: false can read any text file within their scope through two bypass paths. Confirmed on v2.62.2 (commit 860c19d).

The signupHandler in File Browser applies default user permissions via d.settings.Defaults.Apply(user), then strips only Admin (commit a63573b). The Execute permission and Commands list from the default user template are not stripped. When an administrator has enabled signup, server-side execution, and set Execute=true in the default user template, any unauthenticated user who self-registers inherits shell execution capabilities and can run arbitrary commands on the server.

The SPA index page in File Browser is vulnerable to Stored Cross-site Scripting (XSS) via admin-controlled branding fields. An admin who sets branding.name to a malicious payload injects persistent JavaScript that executes for ALL visitors, including unauthenticated users.

The EPUB preview function in File Browser is vulnerable to Stored Cross-site Scripting (XSS). JavaScript embedded in a crafted EPUB file executes in the victim's browser when they preview the file.

The TUS resumable upload handler parses the Upload-Length header as a signed 64-bit integer without validating that the value is non-negative. When a negative value is supplied (e.g. -1), the first PATCH request immediately satisfies the completion condition (newOffset >= uploadLength → 0 >= -1), causing the server to fire after_upload exec hooks with a partial or empty file. An authenticated user with upload permission can trigger any configured after_upload …

Any unauthenticated visitor can register a full administrator account when self-registration ( signup = true ) is enabled and the default user permissions have perm.admin = true. The signup handler blindly applies all default settings - including Perm.Admin - to the new user without any server-side guard that strips admin from self-registered accounts.

The resourcePatchHandler in http/resource.go validates the destination path against configured access rules before the path is cleaned/normalized. The rules engine (rules/rules.go) uses literal string prefix matching (strings.HasPrefix) or regex matching against the raw path. The actual file operation (fileutils.Copy, patchAction) subsequently calls path.Clean() which resolves .. sequences, producing a different effective path than the one validated. This allows an authenticated user with Create or Rename permissions to bypass administrator-configured deny …

A broken access control vulnerability in the TUS protocol DELETE endpoint allows authenticated users with only Create permission to delete arbitrary files and directories within their scope, bypassing the intended Delete permission restriction. Any multi-user deployment where administrators explicitly restrict file deletion for certain users is affected.

When a user creates a public share link for a directory, the withHashFile middleware in http/public.go (line 59) uses filepath.Dir(link.Path) to compute the BasePathFs root. This sets the filesystem root to the parent directory instead of the shared directory itself, allowing anyone with the share link to browse and download files from all sibling directories.

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 …

An authenticated user can bypass the application's "Disallow" file path rules by modifying the request URL. By adding multiple slashes (e.g., //private/) to the path, the authorization check fails to match the rule, while the underlying filesystem resolves the path correctly, granting unauthorized access to restricted files.

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.

It has been found an Insecure Direct Object Reference (IDOR) vulnerability in the FileBrowser application's share deletion functionality. This vulnerability allows any authenticated user with share permissions to delete other users' shared links without authorization checks. The impact is significant as malicious actors can disrupt business operations by systematically removing shared files and links. This leads to denial of service for legitimate users, potential data loss in collaborative environments, and …

The standard library net/http package dependency used by File Browser improperly accepts a bare LF as a line terminator in chunked data chunk-size lines. I can permit request smuggling if a net/http server is used in conjunction with a server that incorrectly accepts a bare LF as part of a chunk-ext. See https://nvd.nist.gov/vuln/detail/CVE-2025-22871 for more details.

File Browser’s authentication system issues long-lived JWT tokens that remain valid even after the user logs out. Please refer to the CWE's listed in this report for further reference and system standards. In summary, the main issue is: Tokens remain valid after logout (session replay attacks) In this report, I used docker as the documentation instruct: docker run \ -v filebrowser_data:/srv \ -v filebrowser_database:/database \ -v filebrowser_config:/config \ -p 8080:80 …

A Denial of Service (DoS) vulnerability exists in the file processing logic when reading a file on endpoint Filebrowser-Server-IP:PORT/files/{file-name} . While the server correctly handles and stores uploaded files, it attempts to load the entire content into memory during read operations without size checks or resource limits. This allows an authenticated user to upload a large file and trigger uncontrolled memory consumption on read, potentially crashing the server and making …

Files managed by the File Browser can be shared with a link to external persons. While the application allows protecting those links with a password, the implementation is error-prone, making an incidental unprotected sharing of a file possible.

In the web application, all users have a scope assigned, and they only have access to the files within that scope. The Command Execution feature of Filebrowser allows the execution of shell commands which are not restricted to the scope, potentially giving an attacker read and write access to all files managed by the server.

All user accounts authenticate towards a File Browser instance with a password. A missing password policy and brute-force protection makes it impossible for administrators to properly secure the authentication process.

The Command Execution feature of Filebrowser only allows the execution of shell command which have been predefined on a user-specific allowlist. The implementation of this allowlist is erroneous, allowing a user to execute additional commands not permitted.

URLs that are accessed by a user are commonly logged in many locations, both server- and client-side. It is thus good practice to never transmit any secret information as part of a URL. The Filebrowser violates this practice, since access tokens are used as GET parameters.

The file access permissions for files uploaded to or created from File Browser are never explicitly set by the application. The same is true for the database used by File Browser. On standard servers where the umask configuration has not been hardened before, this makes all the stated files readable by any operating system account.

The Markdown preview function of File Browser v2.32.0 is vulnerable to Stored Cross-Site-Scripting (XSS). Any JavaScript code that is part of a Markdown file uploaded by a user will be executed by the browser

The Command Execution feature of File Browser only allows the execution of shell command which have been predefined on a user-specific allowlist. Many tools allow the execution of arbitrary different commands, rendering this limitation void.

A Cross-Site Request Forgery vulnerability exists in Filebrowser < 2.18.0 that allows attackers to create a backdoor user with admin privilege and get access to the filesystem via a malicious HTML webpage that is sent to the victim. An admin can run commands using the FileBrowser and hence it leads to RCE.

A Cross-Site Request Forgery vulnerability exists in Filebrowser that allows attackers to create a backdoor user with admin privilege and get access to the filesystem via a malicious HTML webpage that is sent to the victim. An admin can run commands using the FileBrowser and hence it leads to RCE.