CVE-2026-55674
Last modified
CVE-2026-55674 is a critical-severity vulnerability rated 9.3/10 on the CVSS scale. Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, an unauthenticated attacker could send a single request with a crafted color_scheme_id (or dark_scheme_id) cookie to inject arbitrary HTML into a Discourse page. EPSS estimates a 0.36% chance of exploitation in the next 30 days.
Description
Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, an unauthenticated attacker could send a single request with a crafted color_scheme_id (or dark_scheme_id) cookie to inject arbitrary HTML into a Discourse page. Because the cookie value was rendered into a color scheme tag without escaping, the attacker could break out of the attribute and inject a tag that bypassed Discourse's nonce-based Content Security Policy, resulting in arbitrary JavaScript execution in visitors' browsers. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Metrics
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| discourse | discourse | < 2026.1.6; >= 2026.5.0-latest, < 2026.5.2; >= 2026.6.0-latest, < 2026.6.1 |
References
Timeline
- Published
- Last Modified
- Status
- Deferred
Frequently Asked Questions
What is CVE-2026-55674?
How severe is CVE-2026-55674?
How do I fix CVE-2026-55674?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-55669ZITADEL is an open source identity management platform. Prio…4.2
- CVE-2026-5567A flaw has been found in Tenda M3 1.0.0.10. This vulnerabili…8.8
- CVE-2026-55670ZITADEL is an open source identity management platform. Prio…2.3
- CVE-2026-55671ZITADEL is an open source identity management platform. From…2.3
- CVE-2026-55672ZITADEL is an open source identity management platform. Prio…7.4
- CVE-2026-55673PowSyBl (Power System Blocks) is a framework to build power …7.1
- CVE-2026-55676Malcolm is a network traffic analysis tool suite. The file-u…8.8
- CVE-2026-55677Echo is a Go web framework. Prior to 4.15.3 and 5.2.0, Echo'…7.5
- CVE-2026-55678Arc is an open, SQL-native time-series database for telemetr…6.9
- CVE-2026-5568A vulnerability has been found in Akaunting up to 3.1.21. Th…3.5
- CVE-2026-55685React Router is a router for React. In versions 7.0.0 throug…7.5
- CVE-2026-55686Podman is a tool for managing OCI containers and pods. From …5.3
Are you affected by CVE-2026-55674?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST
