Moriyama contribute to Umbraco 6.2.6
Moriyama have contributed a fix to Umbraco version 6 that addresses a performance issue that can see Umbraco sites spiking to utilise 100% of available CPU - and often the site will go down as a direct result.
Update as of June 2022: The blog post about this release on the main Umbraco site is no longer active as newer versions have been made available.