diff --git a/src/aws-cpp-sdk-core/source/internal/AWSHttpResourceClient.cpp b/src/aws-cpp-sdk-core/source/internal/AWSHttpResourceClient.cpp
index 683cf68a953..be617649e34 100644
--- a/src/aws-cpp-sdk-core/source/internal/AWSHttpResourceClient.cpp
+++ b/src/aws-cpp-sdk-core/source/internal/AWSHttpResourceClient.cpp
@@ -10,6 +10,7 @@
 #include <aws/core/http/HttpResponse.h>
 #include <aws/core/utils/logging/LogMacros.h>
 #include <aws/core/utils/ARN.h>
+#include <aws/core/utils/DNS.h>
 #include <aws/core/utils/StringUtils.h>
 #include <aws/core/utils/HashingUtils.h>
 #include <aws/core/platform/Environment.h>
@@ -118,7 +119,6 @@ namespace Aws
             }
             std::shared_ptr<HttpRequest> request(CreateHttpRequest(ss.str(), HttpMethod::HTTP_GET,
                                                                    Aws::Utils::Stream::DefaultResponseStreamFactoryMethod));
-
             request->SetUserAgent(m_userAgent);
 
             if (authToken)
@@ -132,6 +132,11 @@ namespace Aws
         AmazonWebServiceResult<Aws::String> AWSHttpResourceClient::GetResourceWithAWSWebServiceResult(const std::shared_ptr<HttpRequest> &httpRequest) const
         {
             AWS_LOGSTREAM_TRACE(m_logtag.c_str(), "Retrieving credentials from " << httpRequest->GetURIString());
+            if (!Aws::Utils::IsValidHost(httpRequest->GetUri().GetHost())) {
+              AWS_LOGSTREAM_FATAL(m_logtag.c_str(), "Invalid endpoint host constructed: " << httpRequest->GetURIString());
+              return {{}, {}, HttpResponseCode::REQUEST_NOT_MADE};
+            }
+
             if (!m_httpClient)
             {
                 AWS_LOGSTREAM_FATAL(m_logtag.c_str(), "Unable to get a response: missing http client!");
@@ -550,6 +555,7 @@ namespace Aws
             {
                 ss << ".cn";
             }
+
             m_endpoint =  ss.str();
 
             AWS_LOGSTREAM_INFO(STS_RESOURCE_CLIENT_LOG_TAG, "Creating STS ResourceClient with endpoint: " << m_endpoint);
@@ -685,6 +691,7 @@ namespace Aws
             {
                 ss << ".cn";
             }
+
             return ss.str();
         }
 
diff --git a/tests/aws-cpp-sdk-core-tests/aws/auth/AWSCredentialsProviderTest.cpp b/tests/aws-cpp-sdk-core-tests/aws/auth/AWSCredentialsProviderTest.cpp
index b5524217aef..c67272fcd5f 100644
--- a/tests/aws-cpp-sdk-core-tests/aws/auth/AWSCredentialsProviderTest.cpp
+++ b/tests/aws-cpp-sdk-core-tests/aws/auth/AWSCredentialsProviderTest.cpp
@@ -6,7 +6,6 @@
 #include <aws/core/auth/AWSCredentialsProvider.h>
 #include <aws/core/auth/AWSCredentialsProviderChain.h>
 #include <aws/core/auth/SSOCredentialsProvider.h>
-#include <aws/core/auth/STSCredentialsProvider.h>
 #include <aws/core/client/AWSError.h>
 #include <aws/core/client/SpecifiedRetryableErrorsRetryStrategy.h>
 #include <aws/core/config/AWSProfileConfigLoader.h>
@@ -956,6 +955,48 @@ sso_start_url = https://d-92671207e4.awsapps.com/start
     ASSERT_TRUE(mockHttpClient->GetAllRequestsMade().empty());
 }
 
+TEST_F(SSOCredentialsProviderTest, TestInvalidRegionCredentials)
+{
+    AWS_LOGSTREAM_DEBUG("TEST_SSO", "Preparing Test Token file in: " << m_ssoTokenFileName);
+    Aws::OFStream tokenFile(m_ssoTokenFileName.c_str(), Aws::OFStream::out | Aws::OFStream::trunc);
+    tokenFile << R"({
+    "accessToken": "base64string",
+    "expiresAt": ")";
+    tokenFile << DateTime::Now().GetYear() + 1;
+    tokenFile << R"(-01-02T00:00:00Z",
+    "region": "us-west-2",
+    "startUrl": "https://d-92671207e4.awsapps.com/start"
+})";
+    tokenFile.close();
+
+    Aws::OFStream configFile(m_configFileName.c_str(), Aws::OFStream::out | Aws::OFStream::trunc);
+    configFile << R"([default]
+sso_account_id = 012345678901
+sso_region = @amazon.com#
+sso_role_name = SampleRole
+sso_start_url = https://d-92671207e4.awsapps.com/start
+)";
+    configFile.close();
+
+    // Mock DNS/connection failure for invalid region
+    std::shared_ptr<HttpRequest> requestTmp = CreateHttpRequest(URI("https://portal.sso.@amazon.com#.amazonaws.com/federation/credentials"), HttpMethod::HTTP_GET, Aws::Utils::Stream::DefaultResponseStreamFactoryMethod);
+    std::shared_ptr<StandardHttpResponse> dnsFailureResponse = Aws::MakeShared<StandardHttpResponse>(AllocationTag, requestTmp);
+    dnsFailureResponse->SetResponseCode(HttpResponseCode::REQUEST_NOT_MADE);
+    mockHttpClient->AddResponseToReturn(dnsFailureResponse);
+
+    Aws::Config::ReloadCachedConfigFile();
+    SSOCredentialsProvider provider;
+
+    auto creds = provider.GetAWSCredentials();
+    ASSERT_TRUE(creds.IsEmpty());
+    
+    // Check if any requests were made before calling GetMostRecentHttpRequest
+    if (!mockHttpClient->GetAllRequestsMade().empty()) {
+        auto request = mockHttpClient->GetMostRecentHttpRequest();
+        ASSERT_TRUE(request.GetURIString().find("@amazon.com#") != std::string::npos);
+    }
+}
+
 class AWSCredentialsTest : public Aws::Testing::AwsCppSdkGTestSuite
 {
 };
@@ -1120,3 +1161,42 @@ TEST_F(AWSCachedCredentialsTest, ShouldCacheCredenitalAsync)
   ASSERT_TRUE(containCredentials(creds, {"and", "no", "surprises"}));
   ASSERT_FALSE(containCredentials(creds, {"a", "quiet", "life"}));
 }
+
+class STSCredentialsProviderTest : public Aws::Testing::AwsCppSdkGTestSuite {
+public:
+    void SetUp() {
+        mockHttpClient = Aws::MakeShared<MockHttpClient>(AllocationTag);
+        mockHttpClientFactory = Aws::MakeShared<MockHttpClientFactory>(AllocationTag);
+        mockHttpClientFactory->SetClient(mockHttpClient);
+        SetHttpClientFactory(mockHttpClientFactory);
+    }
+
+    void TearDown() {
+        mockHttpClient = nullptr;
+        mockHttpClientFactory = nullptr;
+        CleanupHttp();
+        InitHttp();
+    }
+
+    std::shared_ptr<MockHttpClient> mockHttpClient;
+    std::shared_ptr<MockHttpClientFactory> mockHttpClientFactory;
+};
+
+TEST_F(STSCredentialsProviderTest, TestInvalidRegionCredentials) {
+    ClientConfiguration config;
+    config.region = "@amazon.com#";
+
+    Aws::Internal::STSCredentialsClient stsClient(config);
+    Aws::Internal::STSCredentialsClient::STSAssumeRoleWithWebIdentityRequest request;
+    request.roleArn = "arn:aws:iam::123456789012:role/TestRole";
+    request.roleSessionName = "test-session";
+    request.webIdentityToken = "test-token";
+
+    auto result = stsClient.GetAssumeRoleWithWebIdentityCredentials(request);
+    ASSERT_TRUE(result.creds.IsEmpty());
+
+    if (!mockHttpClient ->GetAllRequestsMade().empty()) {
+        auto httpRequest = mockHttpClient->GetMostRecentHttpRequest();
+        ASSERT_TRUE(httpRequest.GetURIString().find("@amazon.com#") != std::string::npos);
+    }
+}
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