Lemmy up to 0.19.8 activitypub_federation server-side request forgery

Summaryinfo

A vulnerability identified as critical has been detected in Lemmy up to 0.19.8. This affects an unknown function of the component activitypub_federation. This manipulation causes server-side request forgery. This vulnerability is handled as CVE-2025-25194. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Lemmy up to 0.19.8. It has been declared as problematic. Affected by this vulnerability is some unknown functionality of the component activitypub_federation. The manipulation with an unknown input leads to a server-side request forgery vulnerability. The CWE definition for the vulnerability is CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. As an impact it is known to affect confidentiality. The summary by CVE is:

Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. This vulnerability, which is present in versions 0.6.2 and prior of activitypub_federation and versions 0.19.8 and prior of Lemmy, allows a user to bypass any predefined hardcoded URL path or security anti-Localhost mechanism and perform an arbitrary GET request to any Host, Port and URL using a Webfinger Request. As of time of publication, a fix has not been made available.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2025-25194 since 02/03/2025. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/10/2025).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• Lemmy

Version

• 0.19.0
• 0.19.1
• 0.19.2
• 0.19.3
• 0.19.4
• 0.19.5
• 0.19.6
• 0.19.7
• 0.19.8

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion