Solución en Adobe.com

Adobe strongly recommends upgrading to Adobe Reader 8.1.1 or Acrobat 8.1.1. The Adobe Reader 8.1.1 update files can be manually downloaded and installed from:
http://www.adobe.com/support/downloads/product.jsp?product=10&platform=Windows
The Acrobat 8.1.1 update files can be downloaded and installed from:
http://www.adobe.com/support/downloads/product.jsp?product=1&platform=Windows

Microsoft may also be providing an update to resolve this issue at a later date. Please refer to Microsoft Security Advisory 943521 for more information.

Adobe will be providing an update to Adobe Reader 7.0.9 and Acrobat 7.0.9 at a later date. For customers who can not upgrade to Adobe Reader 8.1.1 or Acrobat 8.1.1, administrators can disable the mailto: option in Acrobat, Acrobat 3D and Adobe Reader by modifying the application options in the Windows registry. Additionally, these changes can be added to network deployments to Windows systems.

Disclaimer: This procedure involves editing the registry. Adobe doesn't provide support for editing the registry, which contains critical system and application information. Make sure to back up the registry before modifying it. For more information about the registry, refer to Windows Help.

1. Exit Adobe Reader or Acrobat.
2. Open RegEdit. On Windows XP, go to Start > Run, type in regedit and click OK.
3. Choose File > Export.
4. Select Local Disk C for the Save in: location.
5. Type backup for File Name.
6. Choose All for the Export Range.
7. Click Save.
8. Navigate to the appropriate registry key:
   Acrobat:
   HKEY_LOCAL_MACHINESOFTWAREPoliciesAdobeAdobe Acrobat8.0FeatureLockDowncDefaultLaunchURLPerms
   Reader:
   HKEY_LOCAL_MACHINESOFTWAREPoliciesAdobeAcrobat Reader8.0FeatureLockDowncDefaultLaunchURLPerms
9. If tSchemePerms is set as follows:
   version:1|shell:3|hcp:3|ms-help:3|ms-its:3|ms-
   itss:3|its:3|mk:3|mhtml:3|help:3|disk:3|afp:3|disks:3|telnet:3|ssh:3|acrobat:2|mailto:2|file:2
10. To Disable mailto (recommended)
    Modify tSchemePerms by setting the mailto: value to 3:
    version:1|shell:3|hcp:3|ms-help:3|ms-its:3|ms-
    itss:3|its:3|mk:3|mhtml:3|help:3|disk:3|afp:3|disks:3|telnet:3|ssh:3|acrobat:2|mailto:3|file:2
11. To set mailto to prompt
    Modify tSchemePerms by removing the mailto: value:
    version:1|shell:3|hcp:3|ms-help:3|ms-its:3|ms-
    itss:3|its:3|mk:3|mhtml:3|help:3|disk:3|afp:3|disks:3|telnet:3|ssh:3|acrobat:2|file:2
12. Close RegEdit.
13. Restart the application.