diff --git a/libc/test/src/string/mempcpy_test.cpp b/libc/test/src/string/mempcpy_test.cpp
index 43ad5a0f3e1b7e..877ee8104880eb 100644
--- a/libc/test/src/string/mempcpy_test.cpp
+++ b/libc/test/src/string/mempcpy_test.cpp
@@ -14,7 +14,7 @@
 // mempcpy behavior (returning the end of what was copied).
 TEST(LlvmLibcMempcpyTest, Simple) {
   const char *src = "12345";
-  char dest[10];
+  char dest[10] = {};
   void *result = LIBC_NAMESPACE::mempcpy(dest, src, 6);
   ASSERT_EQ(static_cast<char *>(result), dest + 6);
   ASSERT_STREQ(src, dest);