diff --git a/src/sbbs3/websrvr.c b/src/sbbs3/websrvr.c
index d5e8ef7ce48c8fecf3de692f5f083bb72afac2a9..c9204fc1a0cd5b15ea1c1e3d77d36e4e694a9bc0 100644
--- a/src/sbbs3/websrvr.c
+++ b/src/sbbs3/websrvr.c
@@ -1404,6 +1404,7 @@ static void calculate_digest(http_session_t * session, char *ha1, char *ha2, uns
 	MD5_open(&ctx);
 	MD5_digest(&ctx, ha1, strlen(ha1));
 	MD5_digest(&ctx, ":", 1);
+	/* exception on next line (session->req.auth.nonce==NULL) */
 	MD5_digest(&ctx, session->req.auth.nonce, strlen(session->req.auth.nonce));
 	MD5_digest(&ctx, ":", 1);