CVE-2026-42180

Published: Mag 08, 2026 Last Modified: Mag 08, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 6,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: low
User Interaction: none
Scope: unchanged
Confidentiality: low
Integrity: low
Availability: low

Description

AI Translation Available

Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.19.18, Lemmy allows an authenticated low-privileged user to create a link post through POST /api/v3/post. When a post is created in a public community, the backend asynchronously sends a Webmention to the attacker-controlled link target. The submitted URL is checked for syntax and scheme, but the audited code path does not reject loopback, private, or link-local destinations before the Webmention request is issued. This lets a normal user trigger server-side HTTP requests toward internal services. This issue has been patched in version 0.19.18.

918

Server-Side Request Forgery (SSRF)

Incomplete
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Confidentiality Integrity Access Control
Potential Impacts:
Read Application Data Execute Unauthorized Code Or Commands Bypass Protection Mechanism
Applicable Platforms
Technologies: AI/ML, Web Based, Web Server
View CWE Details
https://github.com/LemmyNet/lemmy/releases/tag/0.19.18
https://github.com/LemmyNet/lemmy/releases/tag/0.19.18
https://github.com/LemmyNet/lemmy/security/advisories/GHSA-…
https://github.com/LemmyNet/lemmy/security/advisories/GHSA-3jvj-v6w2-h948