The 28-year-old Polish keeper, pictured, arrived at Westfield Lane in the summer after previously playing for Polish sides Zawisza and Lechia Gdansk.
A former Polish International, Malkowski made one senior international appearance against Lithuania in March 2011.
In a statement released by the Blues on Thursday night, manager Karl Rose said the keeper's contribution to his fifth placed side's excellent start to the season had prompted the contract offer.
Rose said: “Seb has been excellent in the short space of time he has been with us and we need to protect the side that we are now building so it made sense to secure him on contract.
"He’s vastly experienced at a high level in Poland so this can only help us as we look to improve this season.”
Malkowski will get his first taste of FA Cup action on Saturday when the Premier Division's Blues head to Maltby Main in the FA Cup First Qualifying Round.
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