diff --git a/components/abstractions/lib/microsoft_kiota_abstractions/authentication/allowed_hosts_validator.rb b/components/abstractions/lib/microsoft_kiota_abstractions/authentication/allowed_hosts_validator.rb
index 4463bac..4c403a0 100644
--- a/components/abstractions/lib/microsoft_kiota_abstractions/authentication/allowed_hosts_validator.rb
+++ b/components/abstractions/lib/microsoft_kiota_abstractions/authentication/allowed_hosts_validator.rb
@@ -6,6 +6,8 @@ module MicrosoftKiotaAbstractions
   # Maintains a list of valid hosts and allows authentication providers to check whether
   # a host is valid before authenticating a request
   class AllowedHostsValidator
+    LOCALHOST_STRINGS = ['localhost', '::1', '[::1]', '127.0.0.1'].freeze
+
     # creates a new AllocatedHostsValidator with provided values
     def initialize(allowed_hosts)
       self.allowed_hosts = allowed_hosts
@@ -24,15 +26,25 @@ def allowed_hosts=(val)
 
     # checks whether the provided host is valid
     def url_host_valid?(url)
-      return true if @allowed_hosts.empty?
+      return false if url.nil?
 
       parsed_url = URI(url)
       return false if parsed_url.host.nil?
 
-      return false unless parsed_url.is_a?(URI::HTTPS)
+      is_https = parsed_url.is_a?(URI::HTTPS)
+      is_http_localhost = parsed_url.is_a?(URI::HTTP) && localhost?(parsed_url)
+      return false unless is_https || is_http_localhost
+
+      return true if @allowed_hosts.empty?
+
+      host = parsed_url.host.downcase
+      return true if @allowed_hosts.key?(host)
+
+      stripped_host = host.delete_prefix('[').delete_suffix(']')
+      return true if @allowed_hosts.key?(stripped_host)
 
-      hostname = parsed_url.host.downcase
-      return true if @allowed_hosts.key? hostname
+      hostname = (parsed_url.hostname || host).downcase
+      return true if @allowed_hosts.key?(hostname)
 
       @allowed_hosts.any? { |allowed_host, _| allowed_host.start_with?('.') && hostname.end_with?(allowed_host) }
     rescue URI::InvalidURIError
@@ -41,5 +53,19 @@ def url_host_valid?(url)
 
     # gets the list of valid hosts
     attr_reader :allowed_hosts
+
+    private
+
+    def localhost?(parsed_url)
+      host = parsed_url.host
+      return false if host.nil?
+
+      return true if LOCALHOST_STRINGS.include?(host.downcase)
+
+      hostname = parsed_url.hostname
+      return false if hostname.nil?
+
+      LOCALHOST_STRINGS.include?(hostname.downcase)
+    end
   end
 end
diff --git a/components/abstractions/lib/microsoft_kiota_abstractions/authentication/base_bearer_token_authentication_provider.rb b/components/abstractions/lib/microsoft_kiota_abstractions/authentication/base_bearer_token_authentication_provider.rb
index 6d476d0..7bbe83c 100644
--- a/components/abstractions/lib/microsoft_kiota_abstractions/authentication/base_bearer_token_authentication_provider.rb
+++ b/components/abstractions/lib/microsoft_kiota_abstractions/authentication/base_bearer_token_authentication_provider.rb
@@ -24,7 +24,8 @@ def authenticate_request(request, additional_properties = {})
         end
       else
         Fiber.new do
-          token = @access_token_provider.get_authorization_token(request.uri, additional_properties).resume
+          auth_fiber = @access_token_provider.get_authorization_token(request.uri, additional_properties)
+          token = auth_fiber.resume if auth_fiber
           request.headers.add(AUTHORIZATION_HEADER_KEY, "Bearer #{token}") unless token.nil? || token.empty?
         end
       end
diff --git a/components/abstractions/spec/base_bearer_token_authentication_provider_spec.rb b/components/abstractions/spec/base_bearer_token_authentication_provider_spec.rb
new file mode 100644
index 0000000..a7fee58
--- /dev/null
+++ b/components/abstractions/spec/base_bearer_token_authentication_provider_spec.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require 'uri'
+require 'microsoft_kiota_abstractions'
+require_relative 'access_token_provider_mock'
+
+RSpec.describe MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider do
+  it 'creates a token authentication provider with existing authorization header' do
+    access_token_provider = AccessTokenProviderMock.new
+    token_provider = MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider.new(access_token_provider)
+    expect(token_provider).not_to be nil
+    request_obj = MicrosoftKiotaAbstractions::RequestInformation.new
+    request_obj.headers.add(
+      MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider::AUTHORIZATION_HEADER_KEY, 'SAMPLE'
+    )
+    token_provider.authenticate_request(request_obj).resume
+    expect(request_obj.headers.get(MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider::AUTHORIZATION_HEADER_KEY).at(0)).to eq 'SAMPLE'
+  end
+
+  it 'creates a token authentication provider with mock access token' do
+    access_token_provider = AccessTokenProviderMock.new
+    token_provider = MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider.new(access_token_provider)
+    expect(token_provider).not_to be nil
+    request_obj = MicrosoftKiotaAbstractions::RequestInformation.new
+    request_obj.uri = 'http://sample.com'
+    token_provider.authenticate_request(request_obj).resume
+    expect(request_obj.headers.get(MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider::AUTHORIZATION_HEADER_KEY).at(0)).to eq "Bearer #{AccessTokenProviderMock::DUMMY_TOKEN}"
+  end
+
+  it 'safely handles nil token or nil fiber from access token provider' do
+    nil_provider = double('AccessTokenProvider', get_authorization_token: nil)
+    token_provider = MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider.new(nil_provider)
+    request_obj = MicrosoftKiotaAbstractions::RequestInformation.new
+    request_obj.uri = 'https://example.com'
+    header_key = MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider::AUTHORIZATION_HEADER_KEY
+    expect { token_provider.authenticate_request(request_obj).resume }.not_to raise_error
+    expect(request_obj.headers.get_all.key?(header_key)).to be(false)
+  end
+end
diff --git a/components/abstractions/spec/microsoft_kiota_abstractions_spec.rb b/components/abstractions/spec/microsoft_kiota_abstractions_spec.rb
index 6218035..3002227 100644
--- a/components/abstractions/spec/microsoft_kiota_abstractions_spec.rb
+++ b/components/abstractions/spec/microsoft_kiota_abstractions_spec.rb
@@ -21,32 +21,6 @@
     token_provider.authenticate_request(nil).resume
   end
 
-  it 'creates a token authentication provider with existing authorization header' do
-    access_token_provider = AccessTokenProviderMock.new
-    token_provider = MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider.new(access_token_provider)
-    expect(token_provider).not_to be nil
-    request_obj = MicrosoftKiotaAbstractions::RequestInformation.new
-    request_obj.headers.add(
-      MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider::AUTHORIZATION_HEADER_KEY, 'SAMPLE'
-    )
-    # Authentication does nothing besides returning an empty Fiber
-    token_provider.authenticate_request(request_obj).resume
-    # The request header should not have changed
-    expect(request_obj.headers.get(MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider::AUTHORIZATION_HEADER_KEY).at(0)).to eq 'SAMPLE'
-  end
-
-  it 'creates a token authentication provider with mock access token' do
-    access_token_provider = AccessTokenProviderMock.new
-    token_provider = MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider.new(access_token_provider)
-    expect(token_provider).not_to be nil
-    request_obj = MicrosoftKiotaAbstractions::RequestInformation.new
-    # We have to set a URI, otherwise the code will fail ("undefined method 'chars' for nil")
-    request_obj.uri = 'http://sample.com'
-    token_provider.authenticate_request(request_obj).resume
-    # The request header should now contain the "DUMMY_TOKEN" value:
-    expect(request_obj.headers.get(MicrosoftKiotaAbstractions::BaseBearerTokenAuthenticationProvider::AUTHORIZATION_HEADER_KEY).at(0)).to eq "Bearer #{AccessTokenProviderMock::DUMMY_TOKEN}"
-  end
-
   it 'returns the raw URI when set via setter' do
     request_obj = MicrosoftKiotaAbstractions::RequestInformation.new
     request_obj.path_parameters['term'] = 'search'
diff --git a/components/abstractions/spec/request_information_uri_spec.rb b/components/abstractions/spec/request_information_uri_spec.rb
index 994c362..ecd49ef 100644
--- a/components/abstractions/spec/request_information_uri_spec.rb
+++ b/components/abstractions/spec/request_information_uri_spec.rb
@@ -64,4 +64,27 @@ def uri_for(template, path_parameters = {}, query_parameters = {})
     expect { validator.allowed_hosts = ['https://bad.com'] }.to raise_error(ArgumentError)
     expect(validator.url_host_valid?('https://anything.com')).to be(false)
   end
+
+  it 'validates host with https scheme and allows http for localhost' do
+    validator = described_class.new(['example.com', 'localhost'])
+    expect(validator.url_host_valid?('http://example.com')).to be(false)
+    expect(validator.url_host_valid?('http://localhost:8080')).to be(true)
+    expect(validator.url_host_valid?('https://example.com')).to be(true)
+    expect(validator.url_host_valid?('https://other.com')).to be(false)
+    expect(validator.url_host_valid?('http://other.com')).to be(false)
+  end
+
+  it 'validates IPv6 loopback hosts with both bracketed and unbracketed allowlist entries' do
+    bracketed_validator = described_class.new(['[::1]'])
+    expect(bracketed_validator.url_host_valid?('https://[::1]:8080/v1.0')).to be(true)
+    expect(bracketed_validator.url_host_valid?('http://[::1]:8080/v1.0')).to be(true)
+    expect(bracketed_validator.url_host_valid?('http://example.com')).to be(false)
+    expect(bracketed_validator.url_host_valid?('https://example.com')).to be(false)
+
+    unbracketed_validator = described_class.new(['::1'])
+    expect(unbracketed_validator.url_host_valid?('https://[::1]:8080/v1.0')).to be(true)
+    expect(unbracketed_validator.url_host_valid?('http://[::1]:8080/v1.0')).to be(true)
+    expect(unbracketed_validator.url_host_valid?('http://example.com')).to be(false)
+    expect(unbracketed_validator.url_host_valid?('https://example.com')).to be(false)
+  end
 end
diff --git a/components/authentication/oauth/lib/microsoft_kiota_authentication_oauth/oauth_access_token_provider.rb b/components/authentication/oauth/lib/microsoft_kiota_authentication_oauth/oauth_access_token_provider.rb
index fbb3b60..206d4f0 100644
--- a/components/authentication/oauth/lib/microsoft_kiota_authentication_oauth/oauth_access_token_provider.rb
+++ b/components/authentication/oauth/lib/microsoft_kiota_authentication_oauth/oauth_access_token_provider.rb
@@ -12,6 +12,8 @@
 module MicrosoftKiotaAuthenticationOAuth
   # Access Token Provider class implementation
   class OAuthAccessTokenProvider
+    LOCALHOST_STRINGS = ['localhost', '::1', '[::1]', '127.0.0.1'].freeze
+
     # This is the initializer for OAuthAccessTokenProvider.
     # :params
     #   token_request_context: a instance of one of our token request context or a custom implementation
@@ -48,11 +50,24 @@ def initialize(token_request_context, allowed_hosts = [], scopes = [])
     #   additional_params: hash of symbols to string values, ie { response_mode: 'fragment', prompt: 'login' }
     #                      default is empty hash
     def get_authorization_token(uri, _additional_properties = {})
-      nil if !uri || !@host_validator.url_host_valid?(uri)
+      return Fiber.new { nil } if !uri || uri.to_s.empty?
+
+      begin
+        parsed_url = URI(uri)
+      rescue URI::InvalidURIError, ArgumentError
+        return Fiber.new { nil }
+      end
 
-      parsed_url = URI(uri)
+      return Fiber.new { nil } if parsed_url.nil? || parsed_url.host.nil?
 
-      raise StandardError, 'Only https is supported' if parsed_url.scheme != 'https'
+      https_version = parsed_url.dup
+      https_version.scheme = 'https'
+      return Fiber.new { nil } unless @host_validator.url_host_valid?(https_version.to_s)
+
+      is_localhost = localhost?(parsed_url)
+      is_https = parsed_url.scheme == 'https'
+      is_http_localhost = parsed_url.scheme == 'http' && is_localhost
+      raise StandardError, 'Only https is supported' unless is_https || is_http_localhost
 
       @scopes << "#{parsed_url.scheme}://#{parsed_url.host}/.default" if @scopes.empty?
       @token_request_context.initialize_scopes(@scopes)
@@ -83,5 +98,19 @@ def get_authorization_token(uri, _additional_properties = {})
     protected
 
     attr_writer :host_validator, :token_credential, :scopes, :cached_token
+
+    private
+
+    def localhost?(parsed_url)
+      host = parsed_url.host
+      return false if host.nil?
+
+      return true if LOCALHOST_STRINGS.include?(host.downcase)
+
+      hostname = parsed_url.hostname
+      return false if hostname.nil?
+
+      LOCALHOST_STRINGS.include?(hostname.downcase)
+    end
   end
 end
diff --git a/components/authentication/oauth/spec/oauth_access_token_provider_spec.rb b/components/authentication/oauth/spec/oauth_access_token_provider_spec.rb
new file mode 100644
index 0000000..a0caf9b
--- /dev/null
+++ b/components/authentication/oauth/spec/oauth_access_token_provider_spec.rb
@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+require 'uri'
+require 'microsoft_kiota_abstractions'
+require_relative 'spec_helper'
+
+RSpec.describe MicrosoftKiotaAuthenticationOAuth::OAuthAccessTokenProvider do
+  it 'returns a fiber resolving to nil when uri is nil or not in allowed hosts' do
+    context = MicrosoftKiotaAuthenticationOAuth::ClientCredentialContext.new(
+      'tenant_id', 'client_id', 'client_secret', {}
+    )
+    provider = MicrosoftKiotaAuthenticationOAuth::OAuthAccessTokenProvider.new(context, ['graph.microsoft.com'])
+
+    fiber_nil = provider.get_authorization_token(nil)
+    expect(fiber_nil).to be_a(Fiber)
+    expect(fiber_nil.resume).to be_nil
+
+    fiber_untrusted = provider.get_authorization_token('https://untrusted.com/v1.0')
+    expect(fiber_untrusted).to be_a(Fiber)
+    expect(fiber_untrusted.resume).to be_nil
+
+    fiber_http_untrusted = provider.get_authorization_token('http://untrusted.com/v1.0')
+    expect(fiber_http_untrusted).to be_a(Fiber)
+    expect(fiber_http_untrusted.resume).to be_nil
+
+    fiber_loopback_unapproved = provider.get_authorization_token('http://localhost:8080/v1.0')
+    expect(fiber_loopback_unapproved).to be_a(Fiber)
+    expect(fiber_loopback_unapproved.resume).to be_nil
+  end
+
+  it 'raises error for allowlisted external HTTP target' do
+    context = MicrosoftKiotaAuthenticationOAuth::ClientCredentialContext.new(
+      'tenant_id', 'client_id', 'client_secret', {}
+    )
+    provider = MicrosoftKiotaAuthenticationOAuth::OAuthAccessTokenProvider.new(context, ['graph.microsoft.com'])
+
+    expect do
+      provider.get_authorization_token('http://graph.microsoft.com/v1.0')
+    end.to raise_error(StandardError, 'Only https is supported')
+  end
+
+  it 'allows http on localhost and loopback addresses when allowed hosts is empty or includes loopback' do
+    context = MicrosoftKiotaAuthenticationOAuth::ClientCredentialContext.new(
+      'tenant_id', 'client_id', 'client_secret', {}
+    )
+    allow(context).to receive(:get_token).and_return(double('token', to_hash: {}, token: 'test_token'))
+
+    ['localhost', '127.0.0.1', '[::1]'].each do |host|
+      url = "http://#{host}:8080/v1.0"
+
+      provider_empty = MicrosoftKiotaAuthenticationOAuth::OAuthAccessTokenProvider.new(context, [])
+      fiber_empty = provider_empty.get_authorization_token(url)
+      expect(fiber_empty).to be_a(Fiber)
+      expect(fiber_empty.resume).to eq('test_token')
+
+      [host, host.delete_prefix('[').delete_suffix(']')].uniq.each do |allowed_entry|
+        provider_allowlisted = MicrosoftKiotaAuthenticationOAuth::OAuthAccessTokenProvider.new(
+          context, [allowed_entry]
+        )
+        fiber_allowlisted = provider_allowlisted.get_authorization_token(url)
+        expect(fiber_allowlisted).to be_a(Fiber)
+        expect(fiber_allowlisted.resume).to eq('test_token')
+      end
+    end
+  end
+
+  it 'raises error for unsupported schemes even on localhost' do
+    context = MicrosoftKiotaAuthenticationOAuth::ClientCredentialContext.new(
+      'tenant_id', 'client_id', 'client_secret', {}
+    )
+    provider = MicrosoftKiotaAuthenticationOAuth::OAuthAccessTokenProvider.new(context, [])
+
+    ['ftp://localhost:8080/v1.0', 'ws://localhost:8080/v1.0', '//localhost:8080/v1.0'].each do |url|
+      expect do
+        provider.get_authorization_token(url)
+      end.to raise_error(StandardError, 'Only https is supported')
+    end
+  end
+
+  it 'leaves request unauthenticated when host is not allowed via OAuthAuthenticationProvider' do
+    context = MicrosoftKiotaAuthenticationOAuth::ClientCredentialContext.new(
+      'tenant_id', 'client_id', 'client_secret', {}
+    )
+    auth_provider = MicrosoftKiotaAuthenticationOAuth::OAuthAuthenticationProvider.new(
+      context, ['graph.microsoft.com'], []
+    )
+    request = MicrosoftKiotaAbstractions::RequestInformation.new
+    request.uri = 'https://untrusted.com/v1.0'
+
+    expect { auth_provider.authenticate_request(request).resume }.not_to raise_error
+    expect(request.headers.get_all.key?('Authorization')).to be(false)
+  end
+
+  it 'authenticates http localhost request via OAuthAuthenticationProvider' do
+    context = MicrosoftKiotaAuthenticationOAuth::ClientCredentialContext.new(
+      'tenant_id', 'client_id', 'client_secret', {}
+    )
+    allow(context).to receive(:get_token).and_return(double('token', to_hash: {}, token: 'test_token'))
+
+    auth_provider = MicrosoftKiotaAuthenticationOAuth::OAuthAuthenticationProvider.new(
+      context, ['localhost'], []
+    )
+    request = MicrosoftKiotaAbstractions::RequestInformation.new
+    request.uri = 'http://localhost:8080/v1.0'
+
+    auth_provider.authenticate_request(request).resume
+    expect(request.headers.get('Authorization').first).to eq('Bearer test_token')
+  end
+end