This problem turns a user's system into an endless crash-boot-crash-loop if he tries to load a bad animated cursor file.
The software giant said it originally planned to release this patch as part of its monthly update cycle on April 10 but because malicious code that takes advantage of this bug has already appeared on the Internet the company decided to release the patch on April 3.
Microsoft says the risk is low but advises to install the patch as soon as it becomes available.