{"id":"EUVD-2026-28819","enisaUuid":"014052ac-e936-364a-8a29-0f3fec25f914","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.","datePublished":"May 8, 2026, 7:29:04 PM","dateUpdated":"May 13, 2026, 5:18:23 PM","baseScore":6.3,"baseScoreVersion":"3.1","baseScoreVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L","references":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-3jvj-v6w2-h948\nhttps://github.com/LemmyNet/lemmy/releases/tag/0.19.18\n","aliases":"CVE-2026-42180\n","assigner":"GitHub_M","epss":0.18,"enisaIdProduct":[{"id":"0591a8ef-4915-34c6-bbcc-42300d60ccaa","product":{"name":"lemmy","vendor":{"name":"LemmyNet"}},"product_version":"\u003c 0.19.18"}],"enisaIdVendor":[{"id":"64de4dba-8b23-3a23-837c-b1da6866d4f1","vendor":{"name":"LemmyNet"}}],"enisaIdVulnerability":[{"id":"e6785129-435b-3cb2-aa4b-92d9ccb603b7","vulnerability":{"id":"CVE-2026-42180","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.","datePublished":"May 8, 2026, 7:29:04 PM","dateUpdated":"May 13, 2026, 5:18:23 PM","status":"PUBLISHED","baseScore":6.3,"baseScoreVersion":"3.1","baseScoreVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L","references":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-3jvj-v6w2-h948\nhttps://github.com/LemmyNet/lemmy/releases/tag/0.19.18\n","enisa_id":"EUVD-2026-28819\n","assigner":"GitHub_M","epss":0.18,"dataProcessed":"Nov 7, 2026, 7:21:17 AM","vulnerabilityProduct":[{"id":"1c0fd3f4-f2e7-3037-9c7d-1641dbd6ce39","product":{"name":"lemmy","vendor":{"name":"LemmyNet"}},"product_version":"\u003c 0.19.18"}],"vulnerabilityVendor":[{"id":"87621e45-d9c8-3f54-bf33-294526ea0157","vendor":{"name":"LemmyNet"}}]}}],"enisaIdAdvisory":[]}