CVE-2026-32759
HighCVSS 8.1Exploitation Probability (EPSS)
Low risk35th percentile - higher than 35% of all known CVEs
Summary
In the File Browser file management interface in versions 2.x prior to 2.33.8, there is a vulnerability related to the TUS upload handling that does not validate the Upload-Length header value as non-negative. This allows an authenticated user to supply a negative value, leading to the execution of exec hooks with empty or partial files.
Risk Assessment
This vulnerability can lead to DoS attacks, command injection amplification, and abuse in upload-driven workflows. If exec hooks are enabled, the risk of remote command execution increases.
Recommendation
It is recommended to upgrade to version 2.33.8 or later and disable the enableExec feature to minimize risk. Administrators should also avoid ignoring warnings about known vulnerabilities.
Other vulnerabilities in File Browser
See all- CVE-2026-82236Low
File Browser versions from 2.63.6 through 2.63.23 fail to clean up public share links when a privileged user deletes another user's shared file. Attackers can access the surviving share link to retrieve new unrelated content uploaded to the same path without authentication.
- CVE-2026-72837High
File Browser versions before 2.63.20 fail to honor the createUserDir isolation in proxy and hook authentication auto-provisioning paths. Attackers with valid upstream-authenticated credentials can read, modify, delete, and share files belonging to other users by exploiting the server root scope assignment.
- CVE-2026-73612High
File Browser before v2.63.22 fails to validate access rules for descendants during recursive copy, rename, and delete operations, allowing authenticated users to bypass path-based access controls. Attackers can copy, rename, or delete denied files by operating on their allowed parent directory, defeating rule-based isolation for confidentiality and integrity.
- CVE-2026-55668Medium
A vulnerability in File Browser before version 2.63.16 allows an authenticated user with Create and Modify permissions to create attacker-controlled files outside the user's scope. The issue arises because ScopedFs validates the nearest existing ancestor of a dangling symlink as in scope and then follows the symlink during file creation.
- CVE-2026-54089Critical
File Browser is a file management interface that, starting from version 2.0.0-rc.1, allows unauthenticated attackers to impersonate users, including admins, by sending a forged HTTP header. No credentials are required to gain access.
- CVE-2026-54088Critical
File Browser prior to version 2.63.6 had a vulnerability in the Hook Authentication feature that allowed delegating login verification to an external shell command. User-supplied credentials were interpolated into this command string without sanitization, enabling remote attackers to execute arbitrary OS commands before any authentication.
- CVE-2026-62684Low
File Browser prior to 2.63.17 directly serializes the Link storage struct in sharePostHandler, shareListHandler, and shareGetsHandler, exposing password_hash and the bypass token in API responses. An administrator can retrieve these secrets for every user's shares, enabling offline password cracking and direct access to protected shares.
- CVE-2026-73611Medium
File Browser versions from 2.50.0 through 2.63.21 fail to validate JWT expiration when proxy authentication is configured with a non-default logout page. Attackers with a previously valid token can access protected routes and administrative endpoints indefinitely, and exchange expired tokens for fresh ones via the renewal endpoint.
- CVE-2026-62843Medium
A vulnerability in File Browser from version 2.63.6 to 2.63.16 allows a user with upload permission to plant a backslash-named file that escapes the extraction directory when another user downloads and extracts the generated archive. The issue stems from the use of strings.ReplaceAll(nameInArchive, "\", "/") in the archive builder, which turns a POSIX filename such as ..\..\evil.sh into the archive entry ../../evil.sh.
- CVE-2026-62685High
In File Browser before version 2.63.17, when Signup and CreateUserDir are enabled, the cleanUsername() function normalizes usernames in a way that can cause collisions (e.g., 'team/one', 'team one', and 'team-one' map to the same home directory). This allows a second registrant to gain full access to another user's files.
Original NVD description (English source)
File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. In versions on the 2.x branch prior to 2.33.8, the TUS resumable upload handler parses the Upload-Length header as a signed 64-bit integer without validating that the value is non-negative, allowing an authenticated user to supply a negative value that instantly satisfies the upload completion condition upon the first PATCH request. This causes the server to fire after_upload exec hooks with empty or partial files, enabling an attacker to repeatedly trigger any configured hook with arbitrary filenames and zero bytes written. The impact ranges from DoS through expensive processing hooks, to command injection amplification when combined with malicious filenames, to abuse of upload-driven workflows like S3 ingestion or database inserts. Even without exec hooks enabled, the negative Upload-Length creates inconsistent cache entries where files are marked complete but contain no data. All deployments using the TUS upload endpoint (/api/tus) are affected, with the enableExec flag escalating the impact from cache inconsistency to remote command execution. 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.