The Data Security component in Apple iOS before 4.2.10 and 4.3.x before 4.3.5 does not check the basicConstraints parameter during validation of X.509 certificate chains, which allows man-in-the-middle attackers to spoof an SSL server by using a non-CA certificate to sign a certificate for an arbitrary domain.

Use-after-free vulnerability in WebKit, as used in Apple Safari before 5.0.5; iOS before 4.3.2 for iPhone, iPod, and iPad; iOS before 4.2.7 for iPhone 4 (CDMA); and possibly other products allows remote attackers to execute arbitrary code by adding children to a WBR tag and then removing the tag, related to text nodes, as demonstrated by Chaouki Bekrar during a Pwn2Own competition at CanSecWest 2011.