silverbucket webfinger.js up to 2.8.0 lookup host/path/port server-side request forgery

Summaryinfo

A vulnerability was found in silverbucket webfinger.js up to 2.8.0. It has been declared as critical. Affected is the function lookup. Such manipulation of the argument host/path/port leads to server-side request forgery. This vulnerability is listed as CVE-2025-54590. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in silverbucket webfinger.js up to 2.8.0. Affected by this issue is the function lookup. The manipulation of the argument host/path/port with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality. CVE summarizes:

webfinger.js is a TypeScript-based WebFinger client that runs in both browsers and Node.js environments. In versions 2.8.0 and below, the lookup function accepts user addresses for account checking. However, the ActivityPub specification requires preventing access to localhost services in production. This library does not prevent localhost access, only checking for hosts that start with "localhost" and end with a port. Users can exploit this by creating servers that send GET requests with controlled host, path, and port parameters to query services on the instance's host or local network, enabling blind SSRF attacks. This is fixed in version 2.8.1.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2025-54590 since 07/25/2025. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available.

Upgrading to version 2.8.1 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch b5f2f2c957297d25f4d76072963fccaee2e3095a is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-23378). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• JavaScript Library

Vendor

• silverbucket

Name

• webfinger.js

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8.0

License

• open-source

Website

• Product: https://github.com/silverbucket/webfinger.js/

CPE 2.3info

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CPE 2.2info

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Once again VulDB remains the best source for vulnerability data.

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