CVE-2025-23206: AWS Cloud Development Kit IAM OIDC TLS verification bypass

CVE-2025-23206 · Severity: medium · CVSS 4 · Published 2025-01-17

AWS CDK's IAM OIDC custom resource handler disables TLS certificate validation when connecting to OIDC providers to download CA thumbprints. This allows attackers on the network to intercept and redirect connections to unauthorized OIDC providers through man-in-the-middle attacks. While CDK users define the OIDC provider URLs, the disabled validation increases risk if those URLs are compromised or misconfigured.

Technologies: AWS Cloud Development Kit, aws-cdk-lib (npm). Vendors: AWS, npm.

Quick answers

Is CVE-2025-23206 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-23206 being exploited in the wild.
How severe is CVE-2025-23206?
Medium severity, with a CVSS score of 4, published 17 January 2025.
Which products and versions are affected?
AWS Cloud Development Kit before 2.177.0; aws-cdk-lib (npm) SEMVER:introduced=0,fixed=2.177.0.
Is there a fix for CVE-2025-23206?
Yes. aws-cdk-lib (npm): upgrade to 2.177.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-23206 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2025-23206?
Check whether you run AWS Cloud Development Kit or aws-cdk-lib (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • aws-cdk-lib (npm): upgrade to 2.177.0 or later
    npm install aws-cdk-lib@2.177.0

Technical details

The vulnerability is a TLS verification bypass (CWE-347) in the IAM OIDC custom resource handler. The tls.connect method in aws-cdk/packages/@aws-cdk/custom-resource-handlers/lib/aws-iam/oidc-handler/external.ts sets rejectUnauthorized: false, which disables validation against trusted certificate authorities. An attacker capable of network interception (MITM) could redirect OIDC provider connections to an unauthorized server. The code executes in a Lambda environment, which provides some mitigation. The fix is available in CDK v2.177.0 and later; users must also enable the feature flag '@aws-cdk/aws-iam:oidcRejectUnauthorizedConnections' set to true in their cdk.context.json or cdk.json configuration.

Affected products

  • AWS Cloud Development Kit before 2.177.0

Identifiers

  • CVE-2025-23206
  • GHSA-v4mq-x674-ff73

Timeline

  • 2025-01-17: disclosed: Advisory published
  • 2025-02-22: patched: Patch released in CDK v2.177.0

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.