CVE-2026-42181

MEDIUM EPSS 11.0%
Published May 8, 20261mo ago · Modified Jun 17, 20262w ago
6.5 CVSS 3.1
Medium
Find Similar
Published May 8, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago

Description

Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.19.18, Lemmy fetches metadata for user-supplied post URLs and, under the default StoreLinkPreviews image mode, downloads the preview image through local pict-rs. While the top-level page URL is checked against internal IP ranges, the extracted og:image URL is not subject to the same restriction. As a result, an authenticated low-privileged user can submit an attacker-controlled public page whose Open Graph image points to an internal image endpoint. Lemmy will fetch that internal image server-side and store a local thumbnail that can then be served back to users. This issue has been patched in version 0.19.18.

CVSS Details

Base Score
6.5
Exploitability
2.8
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity None
Availability None

Threat Intelligence

EPSS Exploit Probability
11.0% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

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

References 2

  • github.com https://github.com/LemmyNet/lemmy/releases/tag/0.19.18
  • github.com https://github.com/LemmyNet/lemmy/security/advisories/GHSA-h6hf-9846-xwrq

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.