For Precise, Quantal & Saucy versions of Ubuntu, the 26.0+build2-0ubuntu0 version is available on the $(lsb_release -sc)-updates repository, and probably somewhere in the next days it will be updated to latest stable version 27.0 which is already available on http://www.mozilla.org .
For the Trusty version, there is no firefox package available in the trusty-updates repository. Thus, if a Trusty user does not activate the trusty-proposed repositories, is left with an outdated version of the web browser.
Given that Trusty is a development release, i think that it would be safe to assume that it would contain at least the same package versions with previous releases, if not latest.
Please, include Firefox packaging to the trusty-updates repository so that Trusty testers have the latest security and bug fixes available for this package.
Status changed to 'Confirmed' because the bug affects multiple users.