What is the severity of CVE-2026-22611?

CVE-2026-22611 has a CVSS v3 score of 3.7, which is classified as Low severity.

Is there an exploit available for CVE-2026-22611?

No known public exploits are currently available for CVE-2026-22611.

Is there a patch available for CVE-2026-22611?

Yes, patches are available for CVE-2026-22611. Check the vendor advisories for update instructions.

CVE-2026-22611 - CVE Details, Severity, and Analysis

Q: What is CVE-2026-22611?

### 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 .NET v4. This enhancement validates that a region used to construct an endpoint URL is a valid host label. The change was released on Nov 21, 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 of the AWS SDK for .NET V4 prior to the 4.0.139.0 release (the AWS SDK for .NET V3 was not impacted) ### Patches On Nov 21, 2025, an enhancement [1] was made to the AWS SDK for .NET v4 release, which validates the formatting of a region, providing additional safeguards. ### Workarounds No workarounds are needed, but as always developers should ensure that their application is following security best practices: - Implement proper input validation in your application code - Update to the latest AWS SDK for .NET release on a regular basis - Follow AWS security best practices [2] 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 SDK for .NET v4 thanks Guy Arazi for bringing these customer security considerations to our attention through the coordinated disclosure process. [1] https://github.com/aws/aws-sdk-net/pull/4150 [2] https://docs.aws.amazon.com/sdk-for-net/v4/developer-guide/security.html

Severity Scores

CVSS v33.7

CVSS v20.0

Priority Score188.0

EPSS Score0.0

Low

Exploitation LikelihoodMinimal

0.00%EPSS

Very low probability of exploitation

Monitor and patch as resources allow

0.00%

EPSS

3.7

CVSS

No

Exploit

Yes

Patch

Low Priority

no major risk factors

EPSS predicts the probability of exploitation in the next 30 days based on real-world threat data, complementing CVSS severity scores with actual risk assessment.

Description

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 .NET v4. This enhancement validates that a region used to construct an endpoint URL is a valid host label. The change was released on Nov 21, 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 of the AWS SDK for .NET V4 prior to the 4.0.139.0 release (the AWS SDK for .NET V3 was not impacted)

Patches

On Nov 21, 2025, an enhancement [1] was made to the AWS SDK for .NET v4 release, which validates the formatting of a region, providing additional safeguards.

Workarounds

No workarounds are needed, but as always developers should ensure that their application is following security best practices:

Implement proper input validation in your application code
Update to the latest AWS SDK for .NET release on a regular basis
Follow AWS security best practices [2] for SDK configuration

References

Contact AWS Security via the vulnerability reporting page or email [email protected].

Acknowledgement

AWS SDK for .NET v4 thanks Guy Arazi for bringing these customer security considerations to our attention through the coordinated disclosure process.

[1] https://github.com/aws/aws-sdk-net/pull/4150

[2] https://docs.aws.amazon.com/sdk-for-net/v4/developer-guide/security.html

CVSS v3 Breakdown

Attack Vector:Network

Attack Complexity:High

Privileges Required:Network

User Interaction:Network

Scope:Unchanged

Confidentiality:Local

Integrity:Network

Availability:Network