{"id":"CVE-2017-20290","state":"PUBLISHED","title":"Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribed","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.","publishedAt":"2026-10-22T10:57:24.711Z","updatedAt":"2026-10-22T10:57:24.711Z","severity":{"score":5.1,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["Discourse Discourse"],"affected":[{"vendor":"Discourse","product":"Discourse","packageURL":"pkg:github/discourse/discourse","defaultStatus":"unaffected","versions":[{"version":"1.9.0.beta2","status":"affected","lessThan":"1.9.0.beta13","versionType":"custom"}],"repo":"https://github.com/discourse/discourse"}],"references":["https://github.com/discourse/discourse/commit/a6f2533d38","https://github.com/discourse/discourse/commit/6e37f09b19","https://github.com/projectdiscovery/nuclei-templates/blob/main/http/vulnerabilities/other/discourse-xss.yaml","https://www.vulncheck.com/advisories/discourse-1.9.0-beta13-reflected-xss-via-email-unsubscribed"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T19:43:37.076Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2017/20xxx/CVE-2017-20290.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2017-20290","state":"PUBLISHED","datePublished":"2026-10-22T10:57:24.711Z","dateUpdated":"2026-10-22T10:57:24.711Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-10-14T20:25:25.755Z"},"containers":{"cna":{"title":"Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribed","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Discourse","product":"Discourse","packageURL":"pkg:github/discourse/discourse","defaultStatus":"unaffected","versions":[{"version":"1.9.0.beta2","status":"affected","lessThan":"1.9.0.beta13","versionType":"custom"}],"repo":"https://github.com/discourse/discourse"}],"references":[{"url":"https://github.com/discourse/discourse/commit/a6f2533d38","name":"Fix Commit","tags":["patch"]},{"url":"https://github.com/discourse/discourse/commit/6e37f09b19","name":"Introducing Commit","tags":["technical-description","patch"]},{"url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/vulnerabilities/other/discourse-xss.yaml","name":"Nuclei Template","tags":["technical-description"]},{"url":"https://www.vulncheck.com/advisories/discourse-1.9.0-beta13-reflected-xss-via-email-unsubscribed","name":"VulnCheck Advisory: Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribed","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"ACTIVE","vulnConfidentialityImpact":"NONE","subConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","subIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"MEDIUM","baseScore":5.1,"vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE","version":"3.1","baseSeverity":"MEDIUM","baseScore":6.1,"vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-10-22T10:57:24.711Z"},"datePublic":"2017-10-09T00:00:00.000Z","tags":["x_known-exploited-vulnerability","unsupported-when-assigned"],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*","versionStartIncluding":"1.9.0.beta2","versionEndExcluding":"1.9.0.beta13"}]}]}],"credits":[{"lang":"en","value":"The Shadowserver Foundation","type":"reporter"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"vulncheck-kclub"}}}}}