{"id":"EUVD-2026-28819","revision":"15a9e5f175ad4ed4b00970e233dfadc5","records":[{"revision":"15a9e5f175ad4ed4b00970e233dfadc5","observedAt":"2026-11-05T09:00:55.09+00:00","statement":{"source":"euvd","id":"EUVD-2026-28819","aliases":["CVE-2026-42180"],"title":"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 a…","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.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L","score":6.3,"severity":null}],"references":["https://github.com/LemmyNet/lemmy/security/advisories/GHSA-3jvj-v6w2-h948","https://github.com/LemmyNet/lemmy/releases/tag/0.19.18"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-28819","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"May 8, 2026, 7:29:04 PM","dateUpdated":"May 13, 2026, 5:18:23 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-28819","identifiers":["EUVD-2026-28819","CVE-2026-42180"]},"retained":false,"historicalAffected":[]}],"coverage":[]}