A potential vulnerability was found in Darkcoin yesterday, which would allow pool operators to not pay part of the block rewards to DRK masternodes. As masternodes are an integral part of the Darkcoin network, this issue needed to be addressed as soon as possible. A client update will be released very soon, so make sure to upgrade your clients.
The Darkcoin vulnerability was found by the Spreadcoin developer, when doing a random inspection of the DRK code in regards to masternodes and Darksend. According to Mr. Spread, Darkcoin pool operators could bypass paying part of the block rewards to DRK masternodes.