--- a/lib/tre-parse.c
+++ b/lib/tre-parse.c
@@ -1480,6 +1480,8 @@ tre_parse(tre_parse_ctx_t *ctx)
 		      ctx->re++;
 		      while (ctx->re_end - ctx->re >= 0)
 			{
+			  if (i == sizeof(tmp))
+			    return REG_EBRACE;
 			  if (ctx->re[0] == CHAR_RBRACE)
 			    break;
 			  if (tre_isxdigit(ctx->re[0]))