GHSA-hrr4-3wgr-68x3

Summary

Authenticated users can crash the Navidrome server by supplying an excessively large size parameter to /rest/getCoverArt or to a shared-image URL (/share/img/<token>). When processing such requests, the server attempts to create an extremely large resized image, causing uncontrolled memory growth. This triggers the Linux OOM killer, terminates the Navidrome process, and results in a full service outage.

If the system has sufficient memory and survives the allocation, Navidrome then writes these extremely large resized images into its cache directory, allowing an attacker to rapidly exhaust server disk space as well.

Details

Both /rest/getCoverArt and /share/img/<token> accept a size parameter that is passed directly into the image processing routine without any upper bound validation. When a very large integer is provided, Navidrome attempts to generate a resized image of that size. This leads to excessive memory allocation inside the image resizing path.

In the /rest/getCoverArt handler, the value is read as:

size := p.IntOr("size", 0)
imgReader, lastUpdate, err := api.artwork.GetOrPlaceholder(ctx, id, size, square)

Because no limit is enforced, the image subsystem receives the supplied value as-is. When the requested size is extremely large, the process consumes large amounts of RAM until it is killed by the kernel's OOM killer. If the system has enough available memory to complete the resize operation, the resulting oversized image is then written to Navidrome's cache directory, which can quickly fill the server's disk.

The same behavior is reachable through /share/img/<token> as long as the attacker possesses a valid sharing token.

PoC

1. Authenticate normally to obtain access to /rest/getCoverArt or a valid sharing link containing a /share/img/<token> URL.
2. Send a regular request with a small size value, for example:

/rest/getCoverArt?...&size=300&square=true

3. Replace the size parameter...