CVE-2025-54590 json
webfinger.js is vulnerable to Blind SSRF attacks through localhost
published last yr. modified 4mo ago also GHSA-8xq3-w9fx-74rv , EUVD-2025-23378
- cvss
- 6.9
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 53%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm webfinger.js 2.8.1
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Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- last yr.
Exploit prediction
0.71% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.9 | 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 |
| CNA | 4.0 | 6.9 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | webfinger.js | <2.8.1 |
2.8.1 |
Affected products
- silverbucket webfinger.js
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
github.com
/silverbucket/webfinger.js/commit/b5f2f2c957297d25f4d76072963fccaee2e3095a
web
-
github.com
/silverbucket/webfinger.js/security/advisories/GHSA-8xq3-w9fx-74rv
web
-
github.com
/silverbucket/webfinger.js/releases/tag/v2.8.1
web
-
nvd.nist.gov
/vuln/detail/CVE-2025-54590
advisory
-
github.com
/silverbucket/webfinger.js
package
Sources
- CVE List CVE-2025-54590
- GitHub Advisory GHSA-8xq3-w9fx-74rv
- NVD CVE-2025-54590
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.