For further information on the issue in extension "WEC Discussion Forum" (wec_discussion), please read the related advisory TYPO3-SA-2011-003 that
was published today:
http://typo3.org/security/advisory/typo3-sa-2011-003/
In general the TYPO3 Security Team recommends to read the following pages:
The TYPO3 Security Guidelines: https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/Security/Index.html#security-guidelines
Make sure you are subscribed to the TYPO3 Announce List:
http://lists.typo3.org/cgi-bin/mailman/listinfo/typo3-announce
See all TYPO3 security advisories