CVE-2026-42181

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 v3 6.5 MEDIUM

6.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

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

Configurations

No configuration.

History

No history.

Information

Published : 2026-05-08 20:16

Updated : 2026-06-17 10:47

NVD link : CVE-2026-42181

Mitre link : CVE-2026-42181

CVE.ORG link : CVE-2026-42181

JSON object : View

Products Affected

No product.

CWE

CWE-918

Server-Side Request Forgery (SSRF)

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