CVE-2021-47776 umbraco CVE debrief

Who should care

Defenders responsible for Umbraco CMS deployments should assess exposure and potential impact. This includes operators, platform administrators, vulnerability management teams, and security teams. They should verify the vulnerability details and assess potential impact on their deployments. Prioritization should be based on the severity of the vulnerability and the potential impact on the organization.

Why it matters

CVE-2021-47776 is a server-side request forgery vulnerability in Umbraco CMS v8.14.1 that allows attackers to trigger unauthorized server-side requests to external hosts. Defenders should prioritize verifying exposure and assessing potential impact.

• Verify exposure and potential impact on Umbraco CMS deployments
• Assess and restrict access to dashboard and help controller endpoints
• Monitor for suspicious server-side requests

Technical summary

The vulnerability allows attackers to craft malicious requests to the GetContextHelpForPage, GetRemoteDashboardContent, and GetRemoteDashboardCss endpoints to trigger unauthorized server-side requests to external hosts. This server-side request forgery vulnerability in Umbraco CMS v8.14.1 can be exploited by manipulating baseUrl parameters in multiple dashboard and help controller endpoints. Defenders should prioritize verifying exposure and assessing potential impact. The vulnerability is described in the CVE Program record and NVD vulnerability detail page.

Defensive priority

Defenders should prioritize verifying exposure and assessing potential impact.

Recommended defensive actions

• Verify Umbraco CMS version and assess exposure
• Review and restrict access to dashboard and help controller endpoints
• Monitor for suspicious server-side requests
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The vulnerability is described in the CVE Program record and NVD vulnerability detail page. The source item provides additional metadata. Evidence is limited to publicly available information and may not be comprehensive. Defenders should verify the vulnerability details and assess potential impact on their deployments. The CVE record was published on 2026-01-15T15:52:13.737Z and has not been modified since then.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.