CVE-2017-20290
Discourse 1.9.0.beta2 before 1.9.0.beta13 contains a reflected cross-site scripting vulnerability…
- Risk score
- 40/100
- CVSS
- 6.1 v3.1
- Exploit chance (30 days)
- 0.3%
- Published
- 22 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- 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…
- Affected
- See advisory
- Fix
- Upgrade the product to 1.9.0 or later.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 6.1 medium
References
- https://github.com/discourse/discourse/commit/6e37f09b19
- https://github.com/discourse/discourse/commit/a6f2533d38
- 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
Original 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.
Last activity 22 Oct 2026. Patch Forecast updates every hour.