diff --git a/csharp/PhoneNumbers.Test/PhoneNumbers.Test.csproj b/csharp/PhoneNumbers.Test/PhoneNumbers.Test.csproj
index 01ccf41c..eccfd5bf 100644
--- a/csharp/PhoneNumbers.Test/PhoneNumbers.Test.csproj
+++ b/csharp/PhoneNumbers.Test/PhoneNumbers.Test.csproj
@@ -16,7 +16,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="System.Text.RegularExpressions" Version="4.3.1" />
-    <PackageReference Include="xunit" Version="2.6.4" />
+    <PackageReference Include="xunit" Version="2.6.6" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.6">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>