diff --git a/lldb/include/lldb/Utility/OptionDefinition.h b/lldb/include/lldb/Utility/OptionDefinition.h
--- a/lldb/include/lldb/Utility/OptionDefinition.h
+++ b/lldb/include/lldb/Utility/OptionDefinition.h
@@ -12,6 +12,7 @@
 #include "lldb/lldb-enumerations.h"
 #include "lldb/lldb-private-types.h"
 #include "llvm/ADT/StringExtras.h"
+#include <climits>
 #include <cstdint>
 
 namespace lldb_private {
@@ -47,7 +48,9 @@
   /// Whether this has a short option character.
   bool HasShortOption() const {
     // See the short_option documentation for more.
-    return llvm::isPrint(short_option);
+    // Must not have any bits set outside of unsigned char range
+    return !(short_option & ~((1 << CHAR_BIT) - 1)) &&
+           llvm::isPrint(short_option);
   }
 };
 } // namespace lldb_private
diff --git a/lldb/test/API/commands/help/TestHelp.py b/lldb/test/API/commands/help/TestHelp.py
--- a/lldb/test/API/commands/help/TestHelp.py
+++ b/lldb/test/API/commands/help/TestHelp.py
@@ -57,6 +57,11 @@
         self.runCmd("help unsigned-integer")
 
     @no_debug_info_test
+    def test_help_memory_read_should_not_crash_lldb(self):
+        """Command 'help memory read' should not crash lldb."""
+        self.runCmd("help memory read", check=False)
+
+    @no_debug_info_test
     def test_help_should_not_hang_emacsshell(self):
         """Command 'settings set term-width 0' should not hang the help command."""
         self.expect(