VPC Lambda Reaches AWS Services Via NAT Gateway
stack-vpc-lambda-nat-egress
What this rule checks
Detects VPC-attached Lambda functions routing S3/DynamoDB traffic through a NAT Gateway where free Gateway VPC Endpoints would work.
How to fix it
- 1Add Gateway VPC Endpoints for S3/DynamoDB (free) instead of routing AWS service traffic through NAT Gateway
CDK Insights pinpoints the exact file and line in your CDK source for every finding, so you can jump straight to the fix.
Affected resource types
AWS::Lambda::FunctionAWS::EC2::NatGatewayAWS::EC2::VPCEndpointIntentional? Suppress this finding
Sometimes a flag is deliberate — a genuinely public endpoint, say. You can dismiss stack-vpc-lambda-nat-egress and the reason is kept in the report, not silently hidden.
In .cdk-insights.json:
{
"ignoreRules": [
{ "id": "stack-vpc-lambda-nat-egress", "reason": "Why this is intentional" }
]
}Or inline in your CDK code:
Validations.of(scope).acknowledge({
id: 'cdk-insights::stack-vpc-lambda-nat-egress',
reason: 'Why this is intentional',
});Use the rule ID stack-vpc-lambda-nat-egress shown above — not the CDK-* ID from SARIF / GitHub code scanning. To dismiss every finding on one construct instead, use ignorePaths. Suppression docs →
Catch this in your stack
$ npx cdk-insights scanCDK Insights runs this and 144+ other rules locally against your synthesised CDK app — free, no account, your code never leaves your machine.