diff --git a/src/app-layer-parser.c b/src/app-layer-parser.c
index 2b8a59a141..9dd7baeed3 100644
--- a/src/app-layer-parser.c
+++ b/src/app-layer-parser.c
@@ -1431,7 +1431,7 @@ int AppLayerParserParse(ThreadVars *tv, AppLayerParserThreadCtx *alp_tctx, Flow
             goto error;
         } else if (res.status > 0) {
             DEBUG_VALIDATE_BUG_ON(res.consumed > input_len);
-            DEBUG_VALIDATE_BUG_ON(res.needed + res.consumed < input_len);
+            DEBUG_VALIDATE_BUG_ON(res.needed < input_len - res.consumed);
             DEBUG_VALIDATE_BUG_ON(res.needed == 0);
             /* incomplete is only supported for TCP */
             DEBUG_VALIDATE_BUG_ON(f->proto != IPPROTO_TCP);