Earlier this afternoon Apple released two security updates for OS X Lion and 10.6.8 Snow Leopard to address an issue with compromised digital certificates issued by DigiNotar weeks ago.
Available for: Mac OS X v10.6.8, Mac OS X Server v10.6.8, OS X Lion v10.7.1, Lion Server v10.7.1
Impact: An attacker with a privileged network position may intercept user credentials or other sensitive information
Description: Fraudulent certificates were issued by multiple certificate authorities operated by DigiNotar. This issue is addressed by removing DigiNotar from the list of trusted root certificates, from the list of Extended Validation (EV) certificate authorities, and by configuring default system trust settings so that DigiNotar's certificates, including those issued by other authorities, are not trusted.
The updates are available on Software Update, or directly on Apple's Downloads website. DigiNotar's servers were hacked last month, and began issuing false certificates, leading to security concerns among several companies. As Apple also notes, it was possible to remove the certificates manually by deleting the root entries in Keychain Access.