Summary
Authentication bypass vulnerability in navidrome's subsonic endpoint
A security vulnerability has been identified in navidrome's subsonic endpoint, allowing for authentication bypass. This exploit enables unauthorized access to any known account by utilizing a JSON Web Token (JWT) signed with the key "not so secret".
The vulnerability can only be exploited on instances that have never been restarted.
Details
Navidrome supports an extension to the subsonic authentication scheme, where a JWT can be provided using a jwt query parameter instead of the traditional password or token and salt (corresponding to resp. the p or t and s query parameters).
During the first initialization, navidrome generates a random key that is then used by the authentication module to validate JWTs before extracting the username from the sub claim. If for some reason the key cannot be retrieved by the initialization code, a hardcoded value is used instead: "not so secret".
A bug in the order of operations during navidrome startup results in the authentication module initializing before the module responsible for generating and persisting the random key. As a consequence, the authentication module falls back to using the hardcoded value, which remains in use until the instance gets restarted. Additionally, an error that was meant to be logged when the fallback value is used does not get logged due to another bug, preventing the operator from becoming aware of the issue.
The flaw allows the creation of a JWT with the sub claim set to any existing user on the server, signed with the key "not so secret", which can then be used to authenticate against the subsonic endpoint with the chosen user's privileges.
After navidrome is restarted, the random key generated during the previous startup is loaded and the flaw becomes inexploitable.
PoC
Generate a JWT token with the subject "admin", and key "not so secret" (e.g. online on: http://jwtbuilder.jamiekurtz.com; the other parameters can be left in, it doesn't seem that navidrome validates anything). In a shell, assign the token to the variable JWT (for the curl commands below).
$ podman run -d --name navidrome -p 127.0.0.1:4533:4533 -e ND_DEVAUTOCREATEADMINPASSWORD=password docker.io/deluan/navidrome:0.50.1
$ curl "http://localhost:4533/rest/ping.view?c=dummy&v=1&u=admin&jwt=$JWT"
<subsonic-response xmlns="http://subsonic.org/restapi" status="ok" version="1.16.1" type="navidrome" serverVersion="0.50.1 (f69c27d1)" openSubsonic="true"></subsonic-response>
The ND_DEVAUTOCREATEADMINPASSWORD parameter does not influence the bypass, it also works if the admin or extra users are created manually after starting navidrome.
Restarting navidrome prevents the bypass:
$ podman restart navidrome
$ curl "http://localhost:4533/rest/ping.view?c=dummy&v=1&u=admin&jwt=$JWT"
<subsonic-response xmlns="http://subsonic.org/restapi" status="failed" version="1.16.1" type="navidrome" serverVersion="0.50.1 (f69c27d1)" openSubsonic="true"><error code="40" message="Wrong username or password"></error></subsonic-response>
Impact
This authentication bypass vulnerability potentially affects all instances that don't protect the subsonic endpoint /rest/, which is expected to be most instances in a standard deployment, and most instances in the reverse proxy setup too (as the documentation mentions to leave that endpoint unprotected).
The impact is limited by the fact that the flaw becomes inexploitable after a first restart, and the attacker needs to know the username of existing users on the instance.
For each known user, the attacker could mess with (create/delete/change) playlists, bookmarks, media annotations, shares (which are currently global) and radios. He is also able to get the user's email address (which is PII) with the getUser operation. And lastly he can use the media retrieval operations which could potentially affect the availability of the system.
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.
CVE-2023-51442 has a CVSS score of 8.6 (High). The vector is network-reachable, no 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 (0.50.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2023-51442? CVE-2023-51442 is a high-severity improper authentication vulnerability in github.com/navidrome/navidrome (go), affecting versions <= 0.50.1. It is fixed in 0.50.2. The application does not adequately verify the identity of a user, device, or process before granting access.
- How severe is CVE-2023-51442? CVE-2023-51442 has a CVSS score of 8.6 (High). 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.
- Which versions of github.com/navidrome/navidrome are affected by CVE-2023-51442? github.com/navidrome/navidrome (go) versions <= 0.50.1 is affected.
- Is there a fix for CVE-2023-51442? Yes. CVE-2023-51442 is fixed in 0.50.2. Upgrade to this version or later.
- Is CVE-2023-51442 exploitable, and should I be worried? Whether CVE-2023-51442 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
- What actually determines whether CVE-2023-51442 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.
- How do I fix CVE-2023-51442? Upgrade
github.com/navidrome/navidrometo 0.50.2 or later.