Formic acid is generally compatible with borosilicate glass. There are two aspects that one needs to be mindful of when storing formic acid in glass vials or inserts.
Formic acid gradually decomposes to carbon monoxide (CO) and water building up pressure inside the container. The warmer the solution the faster the process. Therefore, formic acid is typically supplied in plastic bottles and is usually refrigerated.
The second property is universal to all solutions stored in glass and is associated with leaching alkali metals (mainly sodium), boron and silicic acids from the surface of the glass containment into the stored solution.