CVE-2025-23206 IAM OIDC custom resource allows connection to unauthorized OIDC provider in aws-cdk
AWS CDK IAM OIDC provider allows insecure TLS connections by default, potentially enabling MITM attacks unless a specific feature flag is enabled.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-23206?
CVE-2025-23206 is a low-severity vulnerability in aws-cdk, published on 17 Jan 2025. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-347
Which versions are affected by CVE-2025-23206?
2 open source packages ship an affected version, including aws-cdk-lib. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
aws-cdk-lib npm | All versions | 2.177.0 |
aws-cdk-lib npm | All versions | 2.177.0 |
Products include Amazon Aws Cloud Development Kit.
How do I fix CVE-2025-23206?
Upgrade aws-cdk-lib to 2.177.0 or later.
Is CVE-2025-23206 being exploited?
There is no known exploitation of CVE-2025-23206 in the wild and no public exploit code.
Other vulnerabilities in aws-cdk
Sources
Also known as GHSA-v4mq-x674-ff73.