CVE-2026-71286 in ember-dynamic-render-template
Summary
by MITRE • 08/05/2026
The render-template component of ember-dynamic-render-template (addon/components/render-template.js) passes its `templateString` property directly into Ember/Glimmer's compileTemplate() (from @ember/template-compilation) with no sanitization, allow-listing, or validation of the input. Because compileTemplate() dynamically compiles and renders the supplied string as a live Handlebars/Glimmer template, any application that renders attacker-influenced data through this component's templateString property is exposed to client-side template injection: an attacker-controlled Handlebars expression is compiled and executed in the context of the rendering component, which can be leveraged for cross-site scripting depending on what helpers/context are exposed to the compiled template.
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Analysis
by VulDB Data Team • 08/05/2026
The vulnerability resides within the ember-dynamic-render-template addon's render-template component where the templateString property undergoes no input validation or sanitization before being passed directly to Ember/Glimmer's compileTemplate function. This architectural flaw creates a critical client-side template injection vector that can be exploited by malicious actors to execute arbitrary code within the application's context. The component operates by accepting attacker-influenced data through its templateString property and immediately compiling it as a Handlebars/Glimmer template without any form of input filtering or security controls.
The technical implementation of this vulnerability stems from the component's failure to implement proper security measures when processing dynamic template content. When compileTemplate() receives the unsanitized templateString, it dynamically compiles the provided string into executable template code that runs within the browser environment. This process bypasses standard security mechanisms that would normally prevent malicious template code from executing, as the addon component lacks any form of allow-listing or validation controls. The vulnerability directly maps to CWE-74, which describes improper neutralization of special elements in output used by a downstream component, and specifically relates to CWE-94, which addresses the execution of arbitrary code through insecure template processing.
The operational impact of this vulnerability extends beyond simple cross-site scripting attacks to encompass full client-side code execution capabilities. An attacker who can influence the templateString property can inject malicious Handlebars expressions that execute within the context of the rendering component, potentially accessing exposed helpers and contextual data that may include sensitive application information or functionality. The severity increases significantly when considering that the compiled template operates within the same security context as legitimate application code, allowing for potential data exfiltration, session hijacking, or privilege escalation within the browser environment.
Mitigation strategies must address both the immediate vulnerability and prevent similar issues in future implementations. Organizations should implement strict input validation and sanitization of all dynamic template content before it reaches the compileTemplate function, utilizing allow-listing approaches that only permit known-safe template constructs. The component should be updated to reject any templateString containing potentially dangerous patterns or expressions, particularly those involving JavaScript execution contexts or data access operations. Security controls should also include runtime monitoring and logging of template compilation activities to detect anomalous usage patterns. This vulnerability aligns with ATT&CK technique T1203, which describes exploitation of vulnerabilities in client-side applications through template injection attacks, emphasizing the need for comprehensive input validation and secure coding practices in frontend frameworks. The fix requires implementing proper security controls that prevent arbitrary code execution while maintaining the legitimate functionality of dynamic template rendering.