AWS Amplify Studio Vulnerability Exposes Users to Arbitrary Code Execution

Amazon Web Services (AWS) has urgently addressed a critical security vulnerability (CVE-2025-4318) in its AWS Amplify Studio platform, which could have allowed attackers to execute arbitrary JavaScript code during UI component rendering.

The flaw, rated 9.5 on the CVSSv4 scale, impacts the amplify-codegen-ui package (versions ≤2.20.2) and was patched in release 2.20.3 on May 5, 2025.

Technical Breakdown of the Vulnerability

The vulnerability stems from improper input validation in the expression-binding function of the amplify-codegen-ui A core tool for generating front-end code from UI Builder entities.

When developers use the create-component command to import component schemas is used, the system fails to sanitize properties before converting them to executable expressions.

For example, a malicious actor with component-creation privileges could inject unvalidated code like:

javascript{
  "componentProperty": "{{escapeJS(userControlledInput)}}"
}

This bypass would allow execution of arbitrary JavaScript during rendering or build processes, potentially compromising backend systems or exfiltrating sensitive data.

Attack Vectors and Impact

• Arbitrary Code Execution: Authenticated attackers could manipulate component schemas to run malicious scripts in rendering contexts.
• Supply Chain Risks: Compromised components might propagate to downstream applications via AWS CLI code generation.
• Data Exfiltration: Attackers could inject keyloggers or credential harvesters disguised as legitimate UI elements.

AWS confirmed no in-the-wild exploits before patching but emphasized the urgency of updates given the flaw’s criticality.

Mitigation Steps

1. Immediate Package Update: bashnpm update @aws-amplify/amplify-codegen-ui@2.20.3 Verify installation via: bashnpm list @aws-amplify/amplify-codegen-ui
2. Forked Code Review: Teams using custom forks must manually backport security fixes from the GitHub advisory GHSA-hf3j-86p7-mfw8.
3. AWS CLI Version Check: bashaws amplify --version Ensure CLI tools are updated to versions supporting the patched package.

Secure Coding Recommendations

To prevent similar issues, AWS and security experts recommend:

• Avoiding Risky Functions: Replace eval(), new Function(), and unsanitized setTimeout/setInterval calls with safer alternatives.
• Input Validation: Implement strict schema validation for UI components using tools like JSON Schema or AWS’s updated sanitization libraries.
• Static Code Analysis: Integrate tools like Snyk Code to detect injection patterns in development pipelines.

Ongoing Monitoring

AWS has updated Amplify Studio’s logging to track component schema changes, enabling detection of suspicious activity via CloudTrail.

Developers should audit existing components for unexpected expression bindings and monitor AWS Security Bulletins for future updates.

This incident underscores the critical need for rigorous input validation in low-code platforms, where auto-generated code can introduce hidden risks.

As AWS Amplify Studio continues to grow in popularity, maintaining strict access controls and update discipline remains paramount for enterprise security teams.

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