CVE-2026-31981: HTML injection in Diagram tab and Graph view in Guardian/CMC before 26.2.0
A Stored HTML Injection vulnerability was discovered in the Diagram tab and Graph view due to a shared input validation function being insufficiently restrictive. An authenticated user with administrative privileges can inject malicious HTML tags into N2OS configuration data through multiple input vectors. When a victim views the affected data in the Diagram tab and Graph view, the injected HTML renders in their browser, enabling phishing and possibly open redirect attacks. Full XSS exploitation and direct information disclosure are prevented by the existing input validation and Content Security Policy configuration.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
N2OS Guardian/CMCto a version that resolves this vulnerability.Fixed in 26.2.0
Event History
Frequently Asked Questions
What is the severity of CVE-2026-31981?
The severity of CVE-2026-31981 is classified as medium with a score of 4.8.
How do I fix CVE-2026-31981?
To fix CVE-2026-31981, ensure that the input validation functions for the Diagram tab and Graph view are sufficiently restrictive to prevent HTML injection.
What type of vulnerability is CVE-2026-31981?
CVE-2026-31981 is a Stored HTML Injection vulnerability affecting the Diagram tab and Graph view.
Who is affected by CVE-2026-31981?
CVE-2026-31981 affects authenticated users with administrative privileges using Guardian/CMC before version 26.2.0.
What is the impact of CVE-2026-31981?
The impact of CVE-2026-31981 includes potential unauthorized execution of malicious HTML within the application.