A critical vulnerability has been discovered in the JavaScript handling within Adobe Reader and Acrobat versions 9.1 and earlier.  According to the announcement, Adobe expects to make available Windows updates for Adobe Reader versions 9.X, 8.X, and 7.X and Acrobat versions 9.X, 8.X, and 7.X, Macintosh updates for Adobe Reader versions 9.X and 8.X and Acrobat versions 9.X and 8.X, as well as Adobe Reader for Unix versions 9.X and 8.X, by May 12th, 2009.  Additionally, there is a second vulnerability specific to Adobe Reader for Unix that will be resolved by this update as well.
In the meantime, you can perform mitigation steps by disabling JavaScript in Reader and Acrobat:

1. Launch Acrobat or Adobe Reader.
2. Select Edit>Preferences
3. Select the JavaScript Category
4. Uncheck the ‘Enable Acrobat JavaScript’ option
5. Click OK

Ref:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=2009-1492
http://cve.mitre.org/cgi-bin/cvename.cgi?name=2009-1493

A critical vulnerability has been discovered in the JavaScript handling within Adobe Reader and Acrobat versions 9.1 and earlier.  According to the announcement, Adobe expects to make available Windows updates for Adobe Reader versions 9.X, 8.X, and 7.X and Acrobat versions 9.X, 8.X, and 7.X, Macintosh updates for Adobe Reader versions 9.X and 8.X and Acrobat versions 9.X and 8.X, as well as Adobe Reader for Unix versions 9.X and 8.X, by May 12th, 2009.  Additionally, there is a second vulnerability specific to Adobe Reader for Unix that will be resolved by this update as well.
In the meantime, you can perform mitigation steps by disabling JavaScript in Reader and Acrobat:

1. Launch Acrobat or Adobe Reader.
2. Select Edit>Preferences
3. Select the JavaScript Category
4. Uncheck the ‘Enable Acrobat JavaScript’ option
5. Click OK

Ref:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=2009-1492
http://cve.mitre.org/cgi-bin/cvename.cgi?name=2009-1493