webfinger.js is vulnerable to Blind SSRF attacks through localhost

CVE Details

Basic Information

Title webfinger.js is vulnerable to Blind SSRF attacks through localhost
Type cve
Published 2025-08-01T18:03:41.619Z
Modified 2025-08-01T18:39:35.748Z

Product Information

Vendor silverbucket
Product webfinger.js
Version < 2.8.1

CVSS Information

Base Score 6.9 (MEDIUM)
Attack 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

Affected Products

  • silverbucket webfinger.js < 2.8.1

Additional Information

CWE List CWE-918
Source GitHub_M

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.

💭 Join the Security Discussion

🔒 Your email address will not be published. Required fields are marked *

⚠️ Please be respectful and constructive in your comments. Security discussions should remain professional.