CVE-2023-35165 — aws-cdk-lib
MEDIUMCVE-2023-35165 is a medium-severity (CVSS 6.6) CWE-863 vulnerability in aws-cdk-lib. 1 public exploit reference exists, so weaponization risk is real. A fix is available for aws-cdk-lib — see the affected versions and patch details below.
AWS CDK EKS overly permissive trust policies
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-35165.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-35165 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
aws-cdk-libnpm@aws-cdk/aws-eksnpmDescription
If you are using the eks.Cluster or eks.FargateCluster construct we need you to take action. Other users are not affected and can stop reading.
Impact
The AWS Cloud Development Kit (CDK) allows for the definition of Amazon Elastic Container Service for Kubernetes (EKS) clusters. eks.Cluster and eks.FargateCluster constructs create two roles that have an overly permissive trust policy.
The first, referred to as the CreationRole, is used by lambda handlers to create the cluster and deploy Kubernetes resources (e.g KubernetesManifest, HelmChart, ...) onto it. Users with CDK version higher or equal to 1.62.0 (including v2 users) will be affected.
The second, referred to as the default MastersRole, is provisioned only if the mastersRole property isn't provided and has permissions to execute kubectl commands on the cluster. Users with CDK version higher or equal to 1.57.0 (including v2 users) will be affected.
Both these roles use the account root principal in their trust policy, which allows any identity in the account with the appropriate sts:AssumeRole permissions to assume it. For example, this can happen if another role in your account has sts:AssumeRole permissions on Resource: "*".
CreationRole
Users with CDK version higher or equal to 1.62.0 (including v2 users). The role in question can be located in the IAM console. It will have the following name pattern:
*-ClusterCreationRole-*
MastersRole
Users with CDK version higher or equal to 1.57.0 (including v2 users) that are not specifying the mastersRole property. The role in question can be located in the IAM console. It will have the following name pattern:
*-MastersRole-*
Patches
The issue has been fixed in versions v1.202.0, v2.80.0. We recommend you upgrade to a fixed version as soon as possible. See Managing Dependencies in the CDK Developer Guide for instructions on how to do this.
The new versions no longer use the account root principal. Instead, they restrict the trust policy to the specific roles of lambda handlers that need it. This introduces some breaking changes that might require you to perform code changes. Refer to https://github.com/aws/aws-cdk/issues/25674 for a detailed discussion of options.
Workarounds
CreationRole
There is no workaround available for CreationRole.
MastersRole
To avoid creating the default MastersRole, use the mastersRole property to explicitly provide a role. For example:
new eks.Cluster(this, 'Cluster', {
...
mastersRole: iam.Role.fromRoleArn(this, 'Admin', 'arn:aws:iam::xxx:role/Admin')
});
References
https://github.com/aws/aws-cdk/issues/25674
If you have any questions or comments about this advisory we ask that you contact AWS/Amazon Security via our vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | aws-cdk-lib | ≥ 2.0.0&&< 2.80.0 | 2.80.0npm install aws-cdk-lib@2.80.0 |
| 📦npm | @aws-cdk/aws-eks | ≥ 1.57.0&&< 1.202.0 | 1.202.0npm install @aws-cdk/aws-eks@1.202.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aws-cdk-lib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update aws-cdk-lib to 2.80.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-35165 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-35165 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-35165. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-35165 in your dependencies?
O3 Security finds CVE-2023-35165 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.