CVE-2025-23221 Fedify has an Infinite loop and Blind SSRF found inside the Webfinger mechanism
Attackers can trigger infinite loops causing denial of service and perform blind SSRF attacks via the Webfinger mechanism in Fedify.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-23221?
CVE-2025-23221 is a medium-severity server-side request forgery vulnerability in dahlia fedify, published on 20 Jan 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2025-23221?
8 open source packages ship an affected version, including @fedify/fedify.
| Package | Affected | Fixed in |
|---|---|---|
@fedify/fedify npm | From 1.0.13 | 1.0.14 |
@fedify/fedify npm | From 1.0.13 | 1.0.14 |
@fedify/fedify npm | From 1.1.10 | 1.1.11 |
@fedify/fedify npm | From 1.1.10 | 1.1.11 |
@fedify/fedify npm | From 1.2.10 | 1.2.11 |
@fedify/fedify npm | From 1.2.10 | 1.2.11 |
2 more packages
@fedify/fedify npm | From 1.3.3 | 1.3.4 |
@fedify/fedify npm | From 1.3.3 | 1.3.4 |
How do I fix CVE-2025-23221?
Upgrade @fedify/fedify to a fixed version for your release line: 1.0.14, 1.1.11, 1.2.11 or 1.3.4.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2025-23221 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-23221 exists.
Sources
Also known as GHSA-c59p-wq67-24wx.