Adobe has released Preliminary Notification of security updates to Acrobat and Reader next Tuesday, December 9. Microsoft schedules updates for Acrobat and Reader regularly on Patch Tuesday every three months.
The vulnerable versions of Reader XI and Acrobat XI are 11.0.09 and earlier. The vulnerable versions of Reader X and Acrobat X are 10.1.12 and earlier.
Adobe says that the updates address critical "vulnerabilities" in the software, but we do not yet know how many there are and how many are critical.
The company gives the updates for all four products a priority rating of 1, which is the most severe and is used to indicate either that the vulnerability is being exploited in the wild or could be easily exploited with severe consequences. Given that these updates are being released on the regular schedule it is less likely that they are known to be used in the wild.
When the updates are released, the Preliminary Notification page will become the Security Bulletin page for the updates.