Apple Security Advisory 2011-07-25-1 - A certificate chain validation issue existed in the handling of X.509 certificates. An attacker with a privileged network position may capture or modify data in sessions protected by SSL/TLS. Other attacks involving X.509 certificate validation may also be possible. This issue is addressed through improved validation of X.509 certificate chains. The iOS 4.3.5 software update addresses this issue.
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