{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42181","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-04-25T01:53:21.582Z","datePublished":"2026-05-08T19:26:07.763Z","dateUpdated":"2026-05-11T16:01:01.124Z"},"containers":{"cna":{"title":"Lemmy: SSRF and internal image disclosure in post link metadata via unvalidated og:image","problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-h6hf-9846-xwrq","tags":["x_refsource_CONFIRM"],"url":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-h6hf-9846-xwrq"},{"name":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.18","tags":["x_refsource_MISC"],"url":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.18"}],"affected":[{"vendor":"LemmyNet","product":"lemmy","versions":[{"version":"< 0.19.18","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-05-08T19:26:07.763Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-h6hf-9846-xwrq","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-h6hf-9846-xwrq","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-11T16:00:57.536211Z","id":"CVE-2026-42181","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-05-11T16:01:01.124Z"}}]}}