Description

Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the `v4_is_invalid()` function in `activitypub-federation-rust` (`src/utils.rs`) does not check for `Ipv4Addr::UNSPECIFIED` (0.0.0.0). An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the SSRF protection introduced by the fix for CVE-2025-25194 (GHSA-7723-35v7-qcxw), and reach localhost services on the target server. Version 0.7.0-beta.9 patches the issue.

INFO

Published Date :

2026-03-27T00:03:35.946Z

Last Modified :

2026-03-30T11:51:10.425Z

Source :

GitHub_M
AFFECTED PRODUCTS

The following products are affected by CVE-2026-33693 vulnerability.

Vendors Products
Lemmynet
  • Lemmy
REFERENCES

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-33693.

URL Resource
https://github.com/LemmyNet/activitypub-federation-rust/commit/4ae8532b17bc35755240b7f55d4a5b7665351599 cve-icon cve-icon
https://github.com/LemmyNet/lemmy/security/advisories/GHSA-q537-8fr5-cw35 cve-icon cve-icon
https://github.com/advisories/GHSA-7723-35v7-qcxw cve-icon cve-icon
Login to claim this CVE

CVSS Vulnerability Scoring System

Detailed values of each vector for above chart.
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact