diff --git a/SECURITY.md b/SECURITY.md
new file mode 100644
index 00000000..034e8480
--- /dev/null
+++ b/SECURITY.md
@@ -0,0 +1,21 @@
+# Security Policy
+
+## Supported Versions
+
+Use this section to tell people about which versions of your project are
+currently being supported with security updates.
+
+| Version | Supported          |
+| ------- | ------------------ |
+| 5.1.x   | :white_check_mark: |
+| 5.0.x   | :x:                |
+| 4.0.x   | :white_check_mark: |
+| < 4.0   | :x:                |
+
+## Reporting a Vulnerability
+
+Use this section to tell people how to report a vulnerability.
+
+Tell them where to go, how often they can expect to get an update on a
+reported vulnerability, what to expect if the vulnerability is accepted or
+declined, etc.
diff --git a/src/uTensor/allocators/arenaAllocator.hpp b/src/uTensor/allocators/arenaAllocator.hpp
index 58433fd5..1c16c1c7 100644
--- a/src/uTensor/allocators/arenaAllocator.hpp
+++ b/src/uTensor/allocators/arenaAllocator.hpp
@@ -13,7 +13,7 @@
 namespace uTensor {
 
 //#define MSB_SET ~( ~( (T)0 ) >> 1 )
-#define MSB_SET (1 << (sizeof(uint32_t) * 8 - 1))
+#define MSB_SET ((uint32_t)1 << (sizeof(uint32_t) * 8 - 1))
 #define BLOCK_INACTIVE ~MSB_SET
 #define BLOCK_LENGTH_MASK ~MSB_SET
 #define BLOCK_ACTIVE MSB_SET