Is it allowed to overtake in the presented situation?

Why?

You may overtake the truck using the left lane for traffic travelling in your direction. The double solid line separates opposing traffic, and you neither cross it nor drive onto it during the manoeuvre. That line does not prohibit this overtake, but you must still take extra care and leave a safe passing gap.

art. 24 ust. 1 i 2 Prawa o ruchu drogowym; § 86 ust. 5 rozporządzenia w sprawie znaków i sygnałów drogowych