Package Instance

JavaScript SDK v2 users should add validation to the region parameter value in or migrate to v3
CVSSv3.1 Rating: 3.7 (LOW)

Summary
This notification is related to the use of specific values for the region input field when calling AWS services. An actor with access to the environment in which the SDK is used could set the region input field to an invalid value. Per the AWS shared responsibility model, customer applications should protect instances appropriately, or implement proper input sanitization checks. The AWS SDK for JavaScript v2 reached end-of-support on September 8, 2025, but a defense-in-depth enhancement has been implemented in AWS SDK for JavaScript v3. Please migrate to that version.

Impact
Customer applications could be configured to improperly route AWS API calls to non-existent or non-AWS hosts. While the SDK itself is functioning as designed, we recommend customers migrate to AWS SDK for JavaScript v3 for continued support and enhanced security features.

Impacted versions: All versions of AWS SDK for JavaScript v2

Patches
No security patch is required, this is an informational advisory.

Workarounds
- Implement proper input sanitization in your application code
- Migrate to AWS SDK for JavaScript v3
- Follow AWS security best practices for SDK configuration

References
Contact AWS Security via the vulnerability reporting page or email [aws-security@amazon.com](mailto:aws-security@amazon.com).

Acknowledgement
AWS Security thanks Guy Arazi for bringing these customer security considerations to our attention through the coordinated disclosure process.

Prototype pollution
In aws-sdk/shared-ini-file-loader, if an attacker submits a malicious INI file to an application that parses it with loadSharedConfigFiles, they will pollute the prototype on the application. This can be exploited further depending on the context.