Information Disclosure via X-Umbraco-Version Header

Description

The 'X-Umbraco-Version' header indicates the specific version of the Umbraco CMS powering the application. Disclosing this version information allows attackers to identify known vulnerabilities, unpatched security flaws, or default configurations tied to that particular release. Malicious actors may then craft exploits targeting Umbraco-specific weaknesses, attempt privilege escalation through vulnerable plugins or components, or launch social engineering attacks referencing known issues. Ultimately, leaking version data broadens the application’s attack surface by providing adversaries with precise details on which Umbraco build is in use.

Remediation

Remove or mask the 'X-Umbraco-Version' header so that external clients cannot discover the CMS version. Adjust your Umbraco or server configuration to suppress technology-identifying headers, and verify that reverse proxies, CDNs, or load balancers do not re-inject them. Keep Umbraco itself, as well as any extensions or plugins, updated with the latest patches to minimize exploitable vulnerabilities. Employ a Web Application Firewall (WAF) or intrusion detection system to detect malicious traffic targeting known Umbraco flaws. Regular security reviews and audits can help ensure that no sensitive version details are disclosed through response headers.

References

Severity

Owasp

Code: A05:2021

Category: Security Misconfiguration

Classification