Firefox ESR update 140.4 that contain some critical security fixes was released on Oct 14th, but there has not been Tor Browser update (14.5.10) since?
The 15.0a4 alpha release includes security fixes in FF 140.4. The 14.5 stable series is still based on FF 128. I believe Tor Browser 15.0 (based on FF 140) is due out any day now.