{"id":"CVE-2017-20290","published":"2026-10-22T11:17:03.220","lastModified":"2026-10-22T11:17:03.360","description":"Discourse 1.9.0.beta2 before 1.9.0.beta13 contains a reflected cross-site scripting vulnerability that allows unauthenticated attackers to inject scripts through the email parameter of /email/unsubscribed. Attackers can craft GET requests with SVG onload payloads, which unsubscribed.html.erb renders unescaped via html_safe, executing JavaScript in victims' browsers. Exploitation evidence was first observed by the Shadowserver Foundation on 2023-10-19.","cvssScore":6.1,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","cwes":["CWE-79"],"vendors":[],"products":[],"references":[{"url":"https://github.com/discourse/discourse/commit/6e37f09b19","tags":[]},{"url":"https://github.com/discourse/discourse/commit/a6f2533d38","tags":[]},{"url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/vulnerabilities/other/discourse-xss.yaml","tags":[]},{"url":"https://www.vulncheck.com/advisories/discourse-1.9.0-beta13-reflected-xss-via-email-unsubscribed","tags":[]}],"exploitRefs":[{"url":"https://github.com/discourse/discourse/commit/6e37f09b19","tags":[]},{"url":"https://github.com/discourse/discourse/commit/a6f2533d38","tags":[]},{"url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/vulnerabilities/other/discourse-xss.yaml","tags":[]}],"hasPoc":true,"ai":null}