CVE-2017-20290 (GCVE-0-2017-20290)

Vulnerability from cvelistv5 – Published: 2026-10-22 10:57 – Updated: 2026-10-22 10:57 X_Known Exploited Vulnerability Unsupported When Assigned
VLAI Previdian
Title
Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribed
Summary
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.
Severity
5.1 (Medium)
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
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 6753 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Discourse Discourse Affected: 1.9.0.beta2 , < 1.9.0.beta13 (custom)
    cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2017-10-09 00:00
Credits
The Shadowserver Foundation
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 2b49d583-217b-4e8f-8d5f-997ee534b3b6

Vulnerability ID: CVE-2017-20290

Status: Confirmed

Status Updated: 2026-10-22 11:10 UTC

Exploited: Yes

Timestamps
First Seen: 2026-10-22
Asserted: 2026-10-22
Scope
Notes: Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribed | Affected: Discourse / Discourse | CVSS: 5.1 (MEDIUM) | Used in malware: unknown | Not yet in CISA KEV: True
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: previdian

Details
Feed Previdian (previdian.com)
Title Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribed
Cve Id CVE-2017-20290
Vendor Discourse
Ghsa Id None
Product Discourse
Added Date 2026-10-22T11:10:50.824Z
Cvss Score 5.1
Epss Score None
Previous Ids
Cvss Severity MEDIUM
Virtual Patch False
Cvss Estimated False
Epss Percentile None
Used In Malware unknown
Vulnerability Id CVE-2017-20290
Ahead Of Cisa Kev None
Not Yet In Cisa Kev True
References
Created: 2026-10-23 12:00 UTC | Updated: 2026-10-23 12:00 UTC
Show details on NVD website
To clipboard 

{
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        {
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          "packageURL": "pkg:github/discourse/discourse",
          "product": "Discourse",
          "repo": "https://github.com/discourse/discourse",
          "vendor": "Discourse",
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              "version": "1.9.0.beta2",
              "versionType": "custom"
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      ],
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  },
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}



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