CVE-2025-52901

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.

Description

Sensitive information in URLs is logged by several components (see the following examples), even if access is protected by TLS.

• The browser history
• The access logs on the affected web server
• Proxy servers or reverse proxy servers
• Third-party servers via the HTTP referrer header

In case attackers can access certain logs, they could read the included sensitive data.

Proof of Concept

When a file is downloaded via the web interface, the JWT is part of the URL:

GET /api/raw/testdir/testfile.txt?auth=eyJh[...]_r4EQ HTTP/1.1
Host: filebrowser.local:8080
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Referer: http://filebrowser.local:8080/files/testdir/
Cookie: auth=eyJh[...]_r4EQ
Upgrade-Insecure-Requests: 1
Priority: u=0, i

This also happens when a new command session is started:

GET /api/command/?auth=eyJh[...]YW8BA HTTP/1.1
Host: filebrowser.local:8080
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Sec-WebSocket-Version: 13
Origin: http://filebrowser.local:8080
Sec-WebSocket-Key: oqQMrF7R34D3lAkj1+ZHTw==
Connection: keep-alive, Upgrade
Cookie: auth=eyJh[...]YW8BA
Pragma: no-cache
Cache-Control: no-cache
Upgrade: websocket

Recommended Countermeasures

Sensitive data like session tokens or user credentials should be transmitted via HTTP headers or the HTTP body only, never in the URL.

Timeline

• 2025-03-27 Identified the vulnerability in version 2.32.0
• 2025-04-11 Contacted the project
• 2025-04-29 Vulnerability disclosed to the project
• 2025-06-25 Uploaded advisories to the project's GitHub repository
• 2025-06-26 CVE ID assigned by GitHub
• 2025-06-26 Fix released in version 2.33.9

References

• CWE-598: Use of GET Request Method With Sensitive Query Strings
• Original Advisory

Credits

• Mathias Tausig (SBA Research)

The JSON Web Token (JWT) which is used as a session identifier will get leaked to anyone having access to the URLs accessed by the user. This will give the attacker full access to the user's account and, in consequence, to all sensitive files the user has access to.

CVE-2025-52901 has a CVSS score of 4.5 (Medium). The vector is reachable from an adjacent network, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.33.9); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-52901? CVE-2025-52901 is a medium-severity security vulnerability in github.com/filebrowser/filebrowser/v2 (go), affecting versions < 2.33.9. It is fixed in 2.33.9.
2. How severe is CVE-2025-52901? CVE-2025-52901 has a CVSS score of 4.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2025-52901?
   • github.com/filebrowser/filebrowser/v2 (go) (versions < 2.33.9)
   • github.com/filebrowser/filebrowser (go) (versions <= 1.11.0)
4. Is there a fix for CVE-2025-52901? Yes. CVE-2025-52901 is fixed in 2.33.9. Upgrade to this version or later.
5. Is CVE-2025-52901 exploitable, and should I be worried? Whether CVE-2025-52901 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-52901 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-52901? Upgrade github.com/filebrowser/filebrowser/v2 to 2.33.9 or later.