Beginning this month, the Redmond software giant will make public in advance how many security fixes it plans to release in its regular monthly bulletin, how severe the problems are and what products are affected.
Microsoft typically releases security patches on the second Tuesday of each month, with the early warnings posted on its security Web site the previous Thursday. Beginning in December, Microsoft also will let people sign up to receive e-mail notifications.
The previous plan was free and open to anyone willing to sign a confidentiality agreement. But because most people weren't aware of the program, critics said the company was excluding most users while providing others with an advantage in safeguarding their computers.
Microsoft has spent the last couple of years trying to improve security in products such as its ubiquitous Windows operating system and popular Office business software.
The company began testing the early-warning program last fall and expanded it in April.