Mozilla has released version 3.6.13 of its popular Firefox web browser.
This new version contains fixes for 11 security holes, nine of which have been given the worst rating of "critical" severity, as the vulnerabilities can be used to run malicious attack code and install software - the user has to do nothing to be hit in this way, just normal browsing is enough.
Fortunately Firefox contains an integrated update mechanism (Help / Check for Updates to kickstart the process) which can help ensure that most users are rapidly upgraded to the latest version.
However, don't dawdle. Malicious hackers could try to exploit the vulnerabilities - described on Mozilla's website - to infect your computer with malware.