Berthier Stock Repair question

Hello,

I recently went to the big show in Tulsa and picked up a few things. One of which was a Berthier 07/15 M16 Infantry Rifle made by Delaunay-Belleville in 1916. Overall, its a nice all matching rifle (rearsenaled at some point to ball N). However, tonight I noticed this crack right behind the trigger guard. I'm not sure if I bumped it by accident or if it was always there, but I am worried that if I start shooting it, it will get worse. Any suggestions on how to fix or stabilize it. I don't want to replace the stock since its matching.

Bernard