A security issue has been reported in TYPO3, which can be exploited by malicious people to bypass certain security restrictions.

The security issue is caused due to an error in the system extension "openid" when using OpenID identities for authentication. This can be exploited to log in to the TYPO3 backend by using a backend user account's OpenID identity.

Successful exploitation requires an enabled system extension "openid" (disabled by default), knowledge of the OpenID identity assigned to a TYPO3 backend user account, and that the attacker and victim have identities from the same OpenID provider.

NOTE: Only OpenID identities from providers, who discard submitted OpenID identities and allow users to choose a different identity, are vulnerable.

The security issue is reported in version 4.3.0. Prior versions may also be affected.

Solution
Update to version 4.3.1.

Provided and/or discovered by
Jeff Segars, TYPO3 Core team.

Changelog
Further details available to Secunia VIM customers

Original Advisory
TYPO3-SA-2010-001:
http://typo3.org/teams/security/security-bulletins/typo3-sa-2010-001/

Deep Links
Links available to Secunia VIM customers