diff --git a/src/ssl.c b/src/ssl.c
index 3c5998410..2454d54cf 100644
--- a/src/ssl.c
+++ b/src/ssl.c
@@ -8050,7 +8050,7 @@ static WOLFSSL_EVP_PKEY* d2iGenericKey(WOLFSSL_EVP_PKEY** out,
 
     WOLFSSL_ENTER("d2iGenericKey");
 
-    if (in == NULL || inSz < 0) {
+    if (in == NULL || *in == NULL || inSz < 0) {
         WOLFSSL_MSG("Bad argument");
         return NULL;
     }
diff --git a/tests/api.c b/tests/api.c
index 40191d607..dae9bbb48 100644
--- a/tests/api.c
+++ b/tests/api.c
@@ -49648,6 +49648,11 @@ static void test_wolfSSL_ERR_strings(void)
     err = wolfSSL_ERR_func_error_string(UNSUPPORTED_SUITE);
     AssertTrue(err != NULL);
     AssertIntEQ((*err == '\0'), 1);
+
+    /* The value -MIN_CODE_E+2 is PEM_R_PROBLEMS_GETTING_PASSWORD. */
+    err = wolfSSL_ERR_lib_error_string(-MIN_CODE_E+2);
+    AssertTrue(err != NULL);
+    AssertIntEQ((*err == '\0'), 1);
 #endif
     printf(resultFmt, passed);
 #endif