diff --git a/src/tpm2/RuntimeCommands.c b/src/tpm2/RuntimeCommands.c
index 7af67fe6..4752b31d 100644
--- a/src/tpm2/RuntimeCommands.c
+++ b/src/tpm2/RuntimeCommands.c
@@ -415,6 +415,8 @@ LIB_EXPORT BOOL
 RuntimeCommandsCheckEnabled(struct RuntimeCommands *RuntimeCommands,
                             TPM_CC                  cc)
 {
+    if (cc > TPM_CC_LAST || cc < TPM_CC_FIRST)
+        return FALSE;
     return RuntimeCommandsCheckEnabledByIdx(RuntimeCommands, CcToIdx(cc));
 }