diff --git a/apache2/msc_json.c b/apache2/msc_json.c
index f80fc18d..16a2fa10 100644
--- a/apache2/msc_json.c
+++ b/apache2/msc_json.c
@@ -359,7 +359,7 @@ int json_process_chunk(modsec_rec *msr, const char *buf, unsigned int size, char
     if (!base_offset) return -1;
 
     /* Feed our parser and catch any errors */
-    msr->json->status = yajl_parse(msr->json->handle, buf, size);
+    msr->json->status = yajl_parse(msr->json->handle, (unsigned char*)base_offset, size);
     if (msr->json->status != yajl_status_ok) {
 	if (msr->json->depth_limit_exceeded) {
            *error_msg = "JSON depth limit exceeded";