diff -Naur a/src/microhttpd/postprocessor.c b/src/microhttpd/postprocessor.c
--- a/src/microhttpd/postprocessor.c	2023-03-13 11:20:38.069141187 +0800
+++ b/src/microhttpd/postprocessor.c	2023-03-13 11:21:37.158002318 +0800
@@ -310,7 +310,7 @@
 	return NULL; /* failed to determine boundary */
       boundary += MHD_STATICSTR_LEN_ ("boundary=");
       blen = strlen (boundary);
-      if ( (blen == 0) ||
+      if ( (blen < 2) ||
            (blen * 2 + 2 > buffer_size) )
         return NULL;            /* (will be) out of memory or invalid boundary */
       if ( (boundary[0] == '"') &&
