CVE-2017-20290 — Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribed
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 param…
Published: 2026-10-22 · CVSS: 5.1 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7