CVE-2017-20290

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

0.26% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 18.2% of scored records. A rank, not a probability.

NVD base score

5.1 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Deferred. NVD last modified this record on 2026-10-22.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-10-22 10:57Z6 DAYS AGO

Last updated

2026-10-22 10:57Z6 DAYS AGO

Reserved

2026-10-14

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

Medium (CVSS 5.1)

CNA CVSS 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

Weaknesses

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base

Data version

5.2

Document digest

54accbb1bce29b5b92a2dbbcccad5f3a068644e3764b8c5d265cd0aefcf0b2fb

• github.comFix Commithttps://github.com/discourse/discourse/commit/a6f2533d38patch
• github.comIntroducing Commithttps://github.com/discourse/discourse/commit/6e37f09b19technical-descriptionpatch
• github.comNuclei Templatehttps://github.com/projectdiscovery/nuclei-templates/blob/main/http/vulnerabilities/other/discourse-xss.yamltechnical-description
• www.vulncheck.comVulnCheck Advisory: Discourse < 1.9.0.beta13 Reflected XSS via /email/unsubscribedhttps://www.vulncheck.com/advisories/discourse-1.9.0-beta13-reflected-xss-via-email-unsubscribedthird-party-advisory