How To Stop A - Crack Link In Glass From Spreading

To apply:

Glass expands in heat and contracts in cold. Avoid using your car's defroster or heater on full blast, and try not to park in direct sunlight, as sudden temperature shifts are the #1 cause of "spider-webbing". 2. Semi-Permanent DIY Repair (Resin Kits) How to Fix Small Windshield Cracks - AutoZone.com

These act as temporary sealants. Clean the area with glass cleaner or rubbing alcohol, then apply a thin layer of clear nail polish or cyanoacrylate (super glue) directly into the crack. Once dry, it helps hold the edges together.

If you can't get to a repair shop immediately, these temporary household solutions can stabilize the crack for a few days.