Trac is a minimalistic web-based project management, wiki and bug tracking system including a Subversion interface.
Christophe Truc discovered that Trac fails to properly sanitize input passed in the URL.
A remote attacker could exploit this to inject and execute malicious script code or to steal cookie-based authentication credentials, potentially compromising the victim's browser.
There is no known workaround at this time.
All Trac users should upgrade to the latest available version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=www-apps/trac-0.9.3"
Note: Users with the vhosts USE flag set should manually use webapp-config to finalize the update.