CVE-2026-27449 — Umbraco.Engage.Forms
HIGHCVE-2026-27449 is a high-severity (CVSS 7.5) CWE-284 vulnerability in Umbraco.Engage.Forms. A fix is available for Umbraco.Engage.Forms — see the affected versions and patch details below.
Umbraco.Engage.Forms Allows Unauthorized Access to Multiple API Endpoints
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-27449.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
Umbraco.Engage.Forms.NETUmbraco.Engage.FormsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Description
A vulnerability has been identified in Umbraco Engage where certain API endpoints are exposed without enforcing authentication or authorization checks. The affected endpoints can be accessed directly over the network without requiring a valid session or user credentials. By supplying a user-controlled identifier parameter (e.g., ?id=), an attacker can retrieve sensitive data associated with arbitrary records.
Because no access control validation is performed, the endpoints are vulnerable to enumeration attacks, allowing attackers to iterate over identifiers and extract data at scale.
Impact
An unauthenticated attacker can retrieve sensitive Engage-related data by directly querying the affected API endpoints. The vulnerability allows arbitrary record access through predictable or enumerable identifiers.
The confidentiality impact is considered high. No direct integrity or availability impact has been identified.
The scope of exposed data depends on the deployment but may include analytics data, tracking data, customer-related information, or other Engage-managed content.
Patches
The vulnerability affects both v16 and v17. Patches have already been released. Users are advised to update to 16.2.1 or 17.1.1
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
References
Are there any links users can visit to find out more?
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Umbraco.Engage.Forms | ≥ 16.0.0&&< 16.2.1 | 16.2.1dotnet add package Umbraco.Engage.Forms --version 16.2.1 |
| .NETNuGet | Umbraco.Engage.Forms | ≥ 17.0.0&&< 17.1.1 | 17.1.1dotnet add package Umbraco.Engage.Forms --version 17.1.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Umbraco.Engage.Forms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Umbraco.Engage.Forms to 16.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27449 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2026-27449 in your dependencies?
Find it across NuGet, including transitive dependencies.