{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/70552?format=json","vulnerability_id":"VCID-weq5-m3c7-c3gq","summary":"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.","aliases":[{"alias":"CVE-2026-42180"},{"alias":"GHSA-3jvj-v6w2-h948"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/1087022?format=json","purl":"pkg:cargo/lemmy_api_common@0.19.18","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:cargo/lemmy_api_common@0.19.18"}],"affected_packages":[],"references":[{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2026-42180","reference_id":"","reference_type":"","scores":[{"value":"0.00044","scoring_system":"epss","scoring_elements":"0.13874","published_at":"2026-06-14T12:55:00Z"},{"value":"0.00044","scoring_system":"epss","scoring_elements":"0.13904","published_at":"2026-06-13T12:55:00Z"},{"value":"0.00044","scoring_system":"epss","scoring_elements":"0.13906","published_at":"2026-06-12T12:55:00Z"},{"value":"0.00044","scoring_system":"epss","scoring_elements":"0.13791","published_at":"2026-06-11T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-42180"},{"reference_url":"https://github.com/LemmyNet/lemmy","reference_id":"","reference_type":"","scores":[{"value":"6.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/LemmyNet/lemmy"},{"reference_url":"https://github.com/LemmyNet/lemmy/commit/1f06693b708020c5c3a3752bd2f1c6006a75e9bc","reference_id":"","reference_type":"","scores":[{"value":"6.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://github.com/LemmyNet/lemmy/commit/1f06693b708020c5c3a3752bd2f1c6006a75e9bc"},{"reference_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42180","reference_id":"","reference_type":"","scores":[{"value":"6.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""}],"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42180"},{"reference_url":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.18","reference_id":"0.19.18","reference_type":"","scores":[{"value":"6.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-05-13T17:17:59Z/"}],"url":"https://github.com/LemmyNet/lemmy/releases/tag/0.19.18"},{"reference_url":"https://github.com/advisories/GHSA-3jvj-v6w2-h948","reference_id":"GHSA-3jvj-v6w2-h948","reference_type":"","scores":[{"value":"MODERATE","scoring_system":"cvssv3.1_qr","scoring_elements":""}],"url":"https://github.com/advisories/GHSA-3jvj-v6w2-h948"},{"reference_url":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-3jvj-v6w2-h948","reference_id":"GHSA-3jvj-v6w2-h948","reference_type":"","scores":[{"value":"6.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"},{"value":"MODERATE","scoring_system":"cvssv3.1_qr","scoring_elements":""},{"value":"MODERATE","scoring_system":"generic_textual","scoring_elements":""},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-05-13T17:17:59Z/"}],"url":"https://github.com/LemmyNet/lemmy/security/advisories/GHSA-3jvj-v6w2-h948"}],"weaknesses":[{"cwe_id":918,"name":"Server-Side Request Forgery (SSRF)","description":"The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination."}],"exploits":[],"severity_range_score":"4.0 - 6.9","exploitability":null,"weighted_severity":null,"risk_score":null,"resource_url":"http://public2.vulnerablecode.io/vulnerabilities/VCID-weq5-m3c7-c3gq"}