diff --git a/srtp/srtp.c b/srtp/srtp.c

index 7e6d9e5..3722fc1 100644

--- a/srtp/srtp.c

+++ b/srtp/srtp.c

@@ -1076,6 +1076,8 @@ srtp_unprotect(srtp_ctx_t *ctx, void *srtp_hdr, int *pkt_octet_len) {

       srtp_hdr_xtnd_t *xtn_hdr = (srtp_hdr_xtnd_t *)enc_start;

       enc_start += (ntohs(xtn_hdr->length) + 1);

     }  

+    if (!((uint8_t*)enc_start < (uint8_t*)hdr + (*pkt_octet_len - tag_len)))

+        return err_status_parse_err;

     enc_octet_len = (uint32_t)(*pkt_octet_len - tag_len 

 			       - ((enc_start - (uint32_t *)hdr) << 2));

   } else {