Fedify has an Infinite loop and Blind SSRF found inside the Webfinger mechanism

published 2025-01-20 21 mo ago modified 2026-06-17 4 mo ago also GHSA-c59p-wq67-24wx , EUVD-2025-0153

cvss: 5.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

Fedify is a TypeScript library for building federated server apps powered by ActivityPub and other standards. This vulnerability allows a user to maneuver the Webfinger mechanism to perform a GET request to any internal resource on any Host, Port, URL combination regardless of present security mechanisms, and forcing the victim’s server into an infinite loop causing Denial of Service. Moreover, this issue can also be maneuvered into performing a Blind SSRF attack. This vulnerability is fixed in 1.0.14, 1.1.11, 1.2.11, and 1.3.4.

Patch / fix

fixed in 1 links 3

npm @fedify/fedify 1.0.14, 1.1.11, 1.2.11, 1.3.4

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 21 mo ago (2025-01-21)

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.4	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:L
GitHub	3.1	5.4	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:L

Affected packages

ecosystem	package	affected	fixed in
npm	@fedify/fedify	>=1.0.13, <1.0.14 >=1.1.10, <1.1.11 >=1.2.10, <1.2.11 >=1.3.3, <1.3.4	1.0.14 1.1.11 1.2.11 1.3.4

Affected products

dahlia fedify

Classification

Weakness

CWE-835 Loop with Unreachable Exit Condition
CWE-918 Server-Side Request Forgery

References

Sources

Fencer Vulns 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.

Summary