Vulnerability · Published Aug 1, 2025 · Assigned by GitHub_M
CVE-2025-54590webfinger.js is vulnerable to Blind SSRF attacks through localhost
Medium 6.9
In plain English
A medium-severity server-side request forgery in webfinger.js from silverbucket. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 54% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | webfinger.js | 2.8.1 | GHSA-8xq3-w9fx-74rv |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| silverbucket | webfinger.js | < 2.8.1 |
Weakness: CWE-918 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N