🛡️ CVE-2026-42181
🟡 CVSS 6.5 — Medium ✅ No Known Exploit CWE-918 NVD
6.5
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

Details

Severity Medium
CVSS Score 6.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CWE CWE-918
Public Exploit ✅ No
Source NVD
Published 2026-04-24
Updated 2026-06-02
Modified 2026-05-13
Fix URL N/A

Affected Packages

Software From version Fixed in
lemmy-api-common — —
unknown — —

Similar Threats

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