Here are a list of known Security issues for Windows Mobile:

1. MMS (MultiMedia Message)
2. Arcsoft MMS Composer
3. File Transfer Anywhere v3.01 Local Server Password Disclosure
4. vxTftpSrv 1.7.0 Remote Code Execution Buffer Overflow Vulnerability
5. vxWeb v.1.1.4 Denial of Service Vulnerability
6. vxFtpSrv 0.9.7 Remote Code Execution Buffer Overflow Vulnerability
7. IE & MIME By Design Loophole
8. Pocket IE Crash/Cross Frame Scripting/URL Obsfucation/Local file access
9. Spb Kiosk Engine Program Bypass
10. SKYPE-SB/2005-003: Heap overflow in networking routine
11. SKYPE-SB/2005-002: Buffer overflow in Skype-specific URI and VCARD import handling
12. Resco Photo Viewer for Pocket PC "PNG" Image Handling Buffer Overflow Vulnerability
13. The Oddessy WiFi client included with the Dell X50 stores the WEP keys as plaintext in the registry
14. Remote Hard Reset Data Wipe and DoS of Pocket Controller v5.0
15. Windows beta webserver for pocket pc: full remote access
16. Vulnerability in Internet Explorer for Windows Mobile
17. Vulnerability in Windows Mobile Pictures & Videos Could Allow Denial of Service Attacks
18. Internet Explorer Denial of Service - CVE-2007-0685
19. Windows Mobile 5.0 Internet Explorer Denial of Service - CVE-2007-0878