For Thai designers, f0nt.com is the go-to repository. This site frequently updates older fonts with community fixes. Search for "Kittithada" and filter by "Updated" (อัปเดตล่าสุด).
You probably want “Kittithada” (or “Kittithada Bold/Regular”) which is often shared online as a free Thai font. The “Light” weight and “45” may have been part of an old filename. kittithada light 45 font free download upd
Once you’ve downloaded the updated .zip file: For Thai designers, f0nt
Since Kittithada is intrinsically linked to the Sarabun project, you can legally download the entire family (including Light weights) for free from Google Fonts. Always check the font's license file or the
The design firm Cadson Demak is the primary source for this typeface.