Critical Angular Vulnerability Enables Code Execution via Malicious SVG Animations
A significant security flaw has been identified in Angular’s template compiler, designated as CVE-2025-66412, which permits attackers to execute arbitrary code by exploiting SVG animation attributes. This vulnerability circumvents Angular’s inherent security measures and impacts applications utilizing versions below 19.2.17, 20.3.15, or 21.0.2.
Understanding the Vulnerability
The core issue lies in the compiler’s inadequate security schema, which fails to appropriately classify and sanitize URL-containing attributes and SVG animation elements. Specifically, attributes like `xlink:href` and `href`, along with SVG animation tags such as `
Mechanism of Exploitation
Attackers can exploit this flaw through two primary vectors:
1. Unsafe URL Attributes: By binding untrusted data to attributes like `xlink:href` or `href`, malicious URLs can be introduced.
2. Manipulated SVG Animations: By assigning untrusted data to the `attributeName` attribute of SVG animations and directing it to sensitive properties, attackers can inject JavaScript payloads into the animation’s values or attributes.
When these compromised elements are activated—either through user interaction or automatically via animation timing—the malicious code executes within the application’s domain.
Potential Consequences
Successful exploitation of this vulnerability can lead to:
– Session Hijacking: Attackers can steal cookies and authentication tokens, gaining unauthorized access to user sessions.
– Data Exfiltration: Sensitive user information can be extracted without consent.
– Unauthorized Actions: Malicious operations can be performed on behalf of users, compromising the integrity of the application.
Conditions for Exploitation
For an attack to be successful, two conditions must be met:
1. The Angular application must render untrusted input—sourced from databases, APIs, or user submissions—and bind it to vulnerable attributes or SVG animation properties.
2. The victim must interact with the compromised element, or the animation must trigger automatically.
Recommended Mitigation Strategies
To address this critical issue, organizations should:
– Upgrade Angular Versions: Immediately update to the patched versions—Angular 19.2.17, 20.3.15, or 21.0.2—as per the GitHub advisory.
– Implement Content Security Policy (CSP) Headers: For Angular 18.x users without an available patch, enforcing robust CSP headers that disallow `javascript:` URLs can serve as an effective mitigation measure.
– Audit Template Bindings: Review and ensure that untrusted data is not bound to vulnerable SVG/MathML attributes or SVG animation `attributeName` properties. Avoid dynamic binding of user-controlled data to these sensitive attributes.
By proactively addressing this vulnerability, developers and organizations can safeguard their applications against potential exploits and maintain the security and trust of their user base.
