CyberSecBulletin
CVE-2025-23206NVD status: Modified

aws-cdk: Improper Verification of Cryptographic Signature

Published Updated By the CyberSecBulletin desk

CVE-2025-23206 is a high-severity improper verification of cryptographic signature vulnerability in aws-cdk from AWS, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected aws-cdk versions: < 2.177.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.33% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Aws Cloud Development Kit to 2.177.0 or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
AWSaws-cdk< 2.177.0Not stated
AmazonAws Cloud Development Kitbefore 2.177.02.177.0

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.01.8LowCNA (github.com)
CVSS 3.18.1HighNVD

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Verification of Cryptographic Signature

The product does not verify, or incorrectly verifies, the cryptographic signature for data.

More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in aws-cdk

All aws-cdk vulnerabilities

Recent Improper Verification of Cryptographic Signature vulnerabilities

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