Red Hat (RHT) CTO Brian Stevens stepped down this week in an unexpected move that some reports are attributing to tension in the executive boardroom.

The company announced the news in a brief statement that included cursory well-wishes from Red Hat CEO Jim Whitehurst, but no indication of the reasons for Stevens's departure.

According to Steven Vaughn-Nichols of ZDNet, however, some Red Hat employees are speculating that Stevens's departure stemmed from tension with Paul Cormier, Red Hat president of products and technologies. Meanwhile, other employees believe Stevens may have chosen to leave because he hoped to move higher up through the executive ranks, and did not see a likelihood for achieving that goal while remaining at Red Hat.

Stevens joined Red Hat in 2001 following a lengthy tenure at Digital Equipment Corporation, where he made important contributions to the X Window System, a core technology that powers the graphical displays of virtually all Unix and Linux platforms today. He had also served as CTO at Mission Critical Linux. At Red Hat, he played a lead role in laying out the company's plans and communicating them publicly.

Cormier will oversee the Red Hat CTO office until the company finds a new executive to fill the position permanently.