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Umbraco CmsApplication · Umbraco

CVE-2021-47776

MEDIUM · 5.3 CVSS v3.1 Published 2026-01-15
No fix yet
No fix has been published. The vendor has not shipped a fixed release or patch. You remain exposed.
See remediation →
62/100
Remediation priority · Elevated
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-918

The server can be induced to make requests to a URL an attacker controls, turning it into a proxy into internal networks and cloud metadata services. It's especially dangerous behind a trusted network boundary. The fix is strict allow-listing of destinations and blocking access to internal address ranges.

General guidance for the server-side request forgery (ssrf) class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Umbraco CmsApplication
Affected:= 8.14.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Recommended fix Moderate confidence

Umbraco CMS 8.14.2 or later (latest 8.x stable release)

  1. Identify the current Umbraco CMS version in use by checking the Umbraco backoffice (Help > About) or the web.config file
  2. Download the latest Umbraco CMS 8.x release from the official Umbraco releases page (releases.umbraco.com)
  3. Review the release notes for the new version to understand any configuration or migration requirements
  4. Create a full backup of the database, website files, and configuration before upgrading
  5. Deploy the new version to a staging environment and test all functionality, particularly the dashboard and help endpoints
  6. If custom packages are used, verify compatibility with the new version
  7. Deploy to production after successful staging validation
  8. Verify the fix by attempting to access the affected endpoints (GetContextHelpForPage, GetRemoteDashboardContent, GetRemoteDashboardCss) with manipulated baseUrl parameters
Caveat Minor version upgrade within 8.x should have minimal breaking changes; review release notes for any deprecation notices

Generated from the published advisory — verify against the referenced sources before acting.

No vendor fix exists Umbraco Cms has not published a patch for this.

There is no version to upgrade to and no patch to apply. Every affected install stays exposed until the vendor ships a fix — or somebody else builds one.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-47776 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
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