CVE-2026-55424 Details
Description
Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, a topic "featured link" was not sufficiently normalized and escaped before being rendered in the topic list, allowing a user who can set a featured link to inject JavaScript when default Content Security Policy protections were modified or disabled. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
A stored cross-site scripting vulnerability has been identified in Discourse, an open-source discussion platform. This issue affects versions prior to 2026.6.0, as well as 2026.5.1, 2026.4.2, and 2026.1.5. The vulnerability arises because the 'featured link' in topics was not properly sanitized before being displayed in the topic list. This flaw allowed users to inject JavaScript into the rendered content, but only on sites that had altered or disabled the default Content Security Policy (CSP) protections).
Users can upgrade to Discourse versions 2026.6.0, 2026.5.1, 2026.4.2, or 2026.1.5, where this vulnerability has been fixed. Alternatively, site owners can keep the Content Security Policy enabled and ensure it does not allow inline scripts, particularly by avoiding 'unsafe-inline' in the 'content_security_policy_script_src' setting. Disabling the 'topic_featured_link_enabled' setting until an upgrade is possible is also recommended.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 10, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| discourse discourse | >= 2026.1.0, < 2026.1.5 >= 2026.4.0, < 2026.4.2 >= 2026.5.0, < 2026.5.1 2026.6.0 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 14, 2026 | Initial Analysis | [email protected] |
| Jul 10, 2026 | CVE Modified | CISA-ADP |
| Jul 9, 2026 | New CVE Received | [email protected] |