CVE ID :CVE-2026-42180 Published : May 8, 2026, 8:16 p.m. | 1 hour, 23 minutes ago Description :Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.19.18, Lemmy allows an authenticated low-privileged user to create a link post through POST /api/v3/post. When a post is created in a public community, the backend asynchronously sends a Webmention to the attacker-controlled link target. The submitted URL is checked for syntax and scheme, but the audited code path does not reject loopback, private, or link-local destinations before the Webmention request is issued. This lets a normal user trigger server-side HTTP requests toward internal services. This issue has been patched in version 0.19.18. Severity: 6.3 | MEDIUM Visit the link for more details, such as CVSS details, affected products, timeline, and more...