diff --git a/eng/Versions.props b/eng/Versions.props
index a3c3903ad1be..833d916670ca 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -294,7 +294,7 @@
     <GrpcAuthVersion>2.64.0</GrpcAuthVersion>
     <GrpcNetClientVersion>2.64.0</GrpcNetClientVersion>
     <GrpcToolsVersion>2.64.0</GrpcToolsVersion>
-    <MessagePackVersion>2.5.108</MessagePackVersion>
+    <MessagePackVersion>2.5.187</MessagePackVersion>
     <MicrosoftIdentityWebVersion>3.0.0</MicrosoftIdentityWebVersion>
     <MicrosoftIdentityWebGraphServiceClientVersion>3.0.0</MicrosoftIdentityWebGraphServiceClientVersion>
     <MicrosoftIdentityWebUIVersion>3.0.0</MicrosoftIdentityWebUIVersion>
diff --git a/src/submodules/MessagePack-CSharp b/src/submodules/MessagePack-CSharp
index 95119056ee8f..9aeb12b9bdb0 160000
--- a/src/submodules/MessagePack-CSharp
+++ b/src/submodules/MessagePack-CSharp
@@ -1 +1 @@
-Subproject commit 95119056ee8f4da1714b055a4f16893afaa73af7
+Subproject commit 9aeb12b9bdb024512ffe2e4bddfa2785dca6e39e