CVE-2026-22611
📋 TL;DR
The AWS SDK for .NET vulnerability allows attackers with environment access to redirect AWS API calls to non-AWS hosts by setting invalid region values. This affects applications using AWS SDK for .NET versions 4.0.0 through 4.0.3.2 that accept external region input.
💻 Affected Systems
- AWS SDK for .NET
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Sensitive AWS API calls could be redirected to attacker-controlled endpoints, potentially exposing credentials, data, or enabling further attacks.
Likely Case
AWS service calls fail or are misdirected, causing application errors or data integrity issues.
If Mitigated
Proper input validation prevents invalid region values, maintaining normal AWS service routing.
🎯 Exploit Status
Exploitation requires environment access to modify region input values.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.0.3.3
Vendor Advisory: https://github.com/aws/aws-sdk-net/security/advisories/GHSA-9cvc-h2w8-phrp
Restart Required: No
Instructions:
1. Update AWS SDK for .NET package to version 4.0.3.3 or later. 2. Rebuild and redeploy affected applications. 3. Test AWS service connectivity.
🔧 Temporary Workarounds
Input Validation
allValidate region input values against AWS region list before passing to SDK.
Environment Hardening
allRestrict environment access to prevent unauthorized region value modification.
🧯 If You Can't Patch
- Implement strict input validation for region parameters
- Monitor AWS SDK logs for unexpected region values or connection failures
🔍 How to Verify
Check if Vulnerable:
Check AWS SDK for .NET package version in project files or installed packages.Check Version:
Check project .csproj file for PackageReference to AWSSDK.* or use NuGet package manager.Verify Fix Applied:
Confirm AWS SDK for .NET version is 4.0.3.3 or higher and test AWS service calls with various region inputs.📡 Detection & Monitoring
Log Indicators:
- AWS SDK errors with invalid region messages
- Unexpected endpoint connections in AWS SDK logs
Network Indicators:
- AWS API calls to non-AWS endpoints
- DNS resolution to unexpected hosts for AWS services
SIEM Query:
Search for AWS SDK error logs containing 'region' or 'endpoint' validation failures.