CVE-2021-47776: UmbracoCms Umbraco CMS Contains A Server-side Vulnerability

MODERATE
Advisory Identifier: GHSA-h66j-xm43-47pp
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CVSS 5.3
CWE-918
Published
Advisory Summary

CVE-2021-47776 is a MODERATE (CVSS 5.3) umbraco cms contains a server-side vulnerability (CWE-918: Server-Side Request Forgery (SSRF)) affecting UmbracoCms libraries in the NuGet ecosystem. The issue involves umbraco cms contains a server-side request forgery vulnerability. Remediation is available in the latest vendor maintenance releases.

CVE-2021-47776 at a Glance

CVE Identifier CVE-2021-47776
GHSA Identifier GHSA-h66j-xm43-47pp
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-918: Server-Side Request Forgery (SSRF)
Affected Product UmbracoCms
Package Ecosystem NuGet
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2021-47776

To remediate this vulnerability, upgrade all affected UmbracoCms dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

UmbracoCms fixed: Latest secure release 
Upgrade UmbracoCms to Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for UmbracoCms

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-47776, inspect your project dependencies for UmbracoCms:

inspect dependencies for UmbracoCms

Analyze the terminal output to locate any version of UmbracoCms in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-918: Server-Side Request Forgery (SSRF), where the web server receives a url or similar request from an upstream component and retrieves the contents of this url, but it does not sufficiently ensure that the request is being sent to the expected destination. In UmbracoCms, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Umbraco CMS v8.14.1 contains a server-side request forgery vulnerability that allows attackers to manipulate baseUrl parameters in multiple dashboard and help controller endpoints. Attackers can craft malicious requests to the GetContextHelpForPage, GetRemoteDashboardContent, and GetRemoteDashboardCss endpoints to trigger unauthorized server-side requests to external hosts.

CVE-2021-47776 Affected UmbracoCms Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
UmbracoCms
nuget/UmbracoCms
NuGet
8.14.1
All 1 versions
8.14.1
None specified

References

NVD — CVE-2021-47776 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-47776
UmbracoCms Source Repository REPOSITORY
https://github.com/umbraco/Umbraco-CMS
our.umbraco.com WEB
https://our.umbraco.com
releases.umbraco.com/all-releases WEB
https://releases.umbraco.com/all-releases
www.exploit-db.com/exploits/50462 WEB
https://www.exploit-db.com/exploits/50462

Frequently Asked Questions

What is CVE-2021-47776?
CVE-2021-47776 is a security vulnerability in UmbracoCms involving Umbraco CMS contains a server-side request forgery vulnerability under CWE-918: Server-Side Request Forgery (SSRF).
Which UmbracoCms versions are affected?
Affected versions include releases prior to current release patches across affected packages: UmbracoCms.
What version fixes CVE-2021-47776?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is UmbracoCms affected?
Yes, UmbracoCms is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2021-47776?
CVE-2021-47776 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2021-47776?
CVE-2021-47776 is classified under CWE-918: Server-Side Request Forgery (SSRF) (The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.).
How can I check NuGet dependencies for CVE-2021-47776?
Run the dependency tree command: 'inspect dependencies for UmbracoCms'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-h66j-xm43-47pp",
  "modified" : "2026-01-15T22:39:22Z",
  "published" : "2026-01-15T18:31:32Z",
  "aliases" : [ "CVE-2021-47776" ],
  "summary" : "Umbraco CMS contains a server-side request forgery vulnerability",
  "details" : "Umbraco CMS v8.14.1 contains a server-side request forgery vulnerability that allows attackers to manipulate baseUrl parameters in multiple dashboard and help controller endpoints. Attackers can craft malicious requests to the GetContextHelpForPage, GetRemoteDashboardContent, and GetRemoteDashboardCss endpoints to trigger unauthorized server-side requests to external hosts.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "NuGet",
      "name" : "UmbracoCms"
    },
    "versions" : [ "8.14.1" ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-47776"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/umbraco/Umbraco-CMS"
  }, {
    "type" : "WEB",
    "url" : "https://our.umbraco.com"
  }, {
    "type" : "WEB",
    "url" : "https://releases.umbraco.com/all-releases"
  }, {
    "type" : "WEB",
    "url" : "https://www.exploit-db.com/exploits/50462"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-918" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-15T22:39:22Z",
    "nvd_published_at" : "2026-01-15T16:16:09Z"
  }
}