CVE-2026-33693

MEDIUM EPSS 27.8%
Published Mar 27, 20263mo ago · Modified Jun 17, 20262w ago
6.5 CVSS 3.1
Medium
Find Similar
Published Mar 27, 2026 3mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
6.5
Exploitability
3.9
Impact
2.5
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Low
Integrity Low
Availability None

Threat Intelligence

EPSS Exploit Probability
27.8% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-918 Server-Side Request Forgery (SSRF) Validation

References 3

  • github.com https://github.com/LemmyNet/activitypub-federation-rust/commit/4ae8532b17bc35755240b7f55d4a5b7665351599
  • github.com https://github.com/LemmyNet/lemmy/security/advisories/GHSA-q537-8fr5-cw35
  • github.com https://github.com/advisories/GHSA-7723-35v7-qcxw

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.