diff --git a/lib/curlx/base64.c b/lib/curlx/base64.c
index dc6e9c001c..5f6887bd5c 100644
--- a/lib/curlx/base64.c
+++ b/lib/curlx/base64.c
@@ -182,7 +182,7 @@ static CURLcode base64_encode(const char *table64,
   *outlen = 0;
 
   if(!insize)
-    insize = strlen(inputbuff);
+    return CURLE_OK;
 
 #if SIZEOF_SIZE_T == 4
   if(insize > UINT_MAX/4)
@@ -240,8 +240,6 @@ static CURLcode base64_encode(const char *table64,
  * encoded data. Size of encoded data is returned in variable pointed by
  * outlen.
  *
- * Input length of 0 indicates input buffer holds a null-terminated string.
- *
  * Returns CURLE_OK on success, otherwise specific error code. Function
  * output shall not be considered valid unless CURLE_OK is returned.
  *
diff --git a/tests/unit/unit1302.c b/tests/unit/unit1302.c
index 54693631ff..a1676699f2 100644
--- a/tests/unit/unit1302.c
+++ b/tests/unit/unit1302.c
@@ -172,7 +172,7 @@ static CURLcode test_unit1302(const char *arg)
       fprintf(stderr, "Test %u URL encoded output length %d instead of %d\n",
               i, (int)olen, (int)e->olen);
     }
-    if(memcmp(out, e->output, e->olen)) {
+    if(out && memcmp(out, e->output, e->olen)) {
       fprintf(stderr, "Test %u URL encoded badly. Got '%s', expected '%s'\n",
               i, out, e->output);
       unitfail++;