diff --git a/programs/fuzz/fuzz_privkey.c b/programs/fuzz/fuzz_privkey.c
index 2a64f57d0..6c968fd54 100644
--- a/programs/fuzz/fuzz_privkey.c
+++ b/programs/fuzz/fuzz_privkey.c
@@ -59,9 +59,11 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
         }
         else
 #endif
-            {
-                ret = 0;
-            }
+        {
+            /* The key is valid but is not of a supported type.
+             * This should not happen. */
+            abort( );
+        }
     }
     mbedtls_pk_free( &pk );
 #else
diff --git a/programs/fuzz/fuzz_pubkey.c b/programs/fuzz/fuzz_pubkey.c
index 95b75211c..9e8035045 100644
--- a/programs/fuzz/fuzz_pubkey.c
+++ b/programs/fuzz/fuzz_pubkey.c
@@ -60,7 +60,9 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
         else
 #endif
         {
-            ret = 0;
+            /* The key is valid but is not of a supported type.
+             * This should not happen. */
+            abort( );
         }
     }
     mbedtls_pk_free( &pk );