“[This could affect] user-level secrets, such as browser history, website content, user keys, and passwords, or system-level secrets, such as disk encryption keys,” they explained.
They added that it was currently unclear whether any such attack would leave a trace, or if anyone had actually exploited the flaw to date.
Intel has said that it believes that carrying out such an attack would be “a very complex undertaking” but is recommending that users download security updates from Microsoft, Apple and Linux-based operating system providers that will address the issue.
The chip-maker has indicated that the biggest performance hit is likely to involve data centre servers handling tasks that use the programming language Java.
One graph shows such activity running at 81% of the speed it used to, once a software patch has been applied.