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.
A defense-in-depth enhancement has been implemented in the AWS SDK for Swift. This enhancement validates that a region used to construct an endpoint URL is a valid host label. The change was released on November 6, 2025. This advisory is informational to help customers understand their responsibilities regarding configuration security.
Impact Customer applications could be configured to improperly route AWS API calls to non-existent or non-AWS hosts. While the SDK was functioning safely within the requirements of the shared responsibility model, additional safeguards have been added to support secure customer implementations.
Impacted versions: All versions prior to 2025-11-06 release (below 1.5.79)
Patches On November 6, 2025 an enhancement was made to the AWS SDK for Swift release, which validates the formatting of a region, providing additional safeguards.
Workarounds No workarounds are needed, but as always you should ensure that your application is following security best practices:
References Contact AWS Security via the vulnerability reporting page or email aws-security@amazon.com.
Acknowledgement AWS SDK thanks Guy Arazi for bringing these customer security considerations to our attention through the coordinated disclosure process.
[1] https://docs.aws.amazon.com/sdk-for-swift/latest/developer-guide/security.html
1.5.79Exploitability
AV:NAC:HPR:NUI:NScope
S:UImpact
C:LI:NA:N3.7/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N