CVE-2025-23206

The AWS Cloud Development Kit (AWS CDK) is an open-source software development framework to define cloud infrastructure in code and provision it through AWS CloudFormation. Users who use IAM OIDC custom resource provider package will download CA Thumbprints as part of the custom resource workflow. However, the current `tls.connect` method will always set `rejectUnauthorized: false` which is a potential security concern. CDK should follow the best practice and set `rejectUnauthorized: true`. However, this could be a breaking change for existing CDK applications and we should fix this with a feature flag. Note that this is marked as low severity Security advisory because the issuer url is provided by CDK users who define the CDK application. If they insist on connecting to a unauthorized OIDC provider, CDK should not disallow this. Additionally, the code block is run in a Lambda environment which mitigate the MITM attack. The patch is in progress. To mitigate, upgrade to CDK v2.177.0 (Expected release date 2025-02-22). Once upgraded, users should make sure the feature flag '@aws-cdk/aws-iam:oidcRejectUnauthorizedConnections' is set to true in `cdk.context.json` or `cdk.json`. There are no known workarounds for this vulnerability.

The following products are affected by CVE-2025-23206 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2025-23206.

URL	Resource
https://docs.aws.amazon.com/cdk/v2/guide/featureflags.html
https://github.com/aws/aws-cdk/blob/d16482fc8a4a3e1f62751f481b770c09034df7d2/packages/%40aws-cdk/custom-resource-handlers/lib/aws-iam/oidc-handler/external.ts#L34
https://github.com/aws/aws-cdk/commit/3e4f3773bfa48b75bf0adc7d53d46bbec7714a9e#diff-38a03353f201fd2e520df67fb43f9f000257bffd6e9acaa5569cce7005a77560
https://github.com/aws/aws-cdk/issues/32920
https://github.com/aws/aws-cdk/pull/32921
https://github.com/aws/aws-cdk/releases/tag/v2.177.0
https://github.com/aws/aws-cdk/security/advisories/GHSA-v4mq-x674-ff73