Lemmy has SSRF and internal image disclosure in post link metadata via unvalidated og:image — CVE-2026-42181

Summary

### Summary 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…

Product

rust: lemmy_api_common

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

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