Microsoft XML Core Services 3.0, 4.0, 5.0, and 6.0 accesses uninitialized memory locations, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-043
http://www.us-cert.gov/cas/techalerts/TA12-192A.html