diff --git a/src/NSubstitute/NSubstitute.csproj b/src/NSubstitute/NSubstitute.csproj
index 20db4d49..c3671493 100644
--- a/src/NSubstitute/NSubstitute.csproj
+++ b/src/NSubstitute/NSubstitute.csproj
@@ -50,7 +50,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Castle.Core" Version="5.1.1" />
+    <PackageReference Include="Castle.Core" Version="5.2.1" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">