SSRF in Silverbucket Webfinger.js
CVE-2025-54590
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
EPSS exploit prediction
EPSS: 0.006 (48.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000
Affected products
- Silverbucket Webfinger.js — versions < 2.8.1
Weakness classification (CWE)
Public proof-of-concept exploits
References
Frequently asked questions
- What is CVE-2025-54590?
- CVE-2025-54590 is a vulnerability in Silverbucket Webfinger.js, classified under Server-Side Request Forgery (SSRF). Published 2025-08-01.
- Is CVE-2025-54590 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.