Work has reportedly begun on updating the Windows and Linux operating systems, with Mac OS likely to follow to address a decade-old security flaw in Intel chips discovered only in late 2017.

The impact of the flaw is potentially huge because Intel’s microprocessors are found in millions of internet and corporate servers as well as business and consumer PCs, with the performance degradation of the security patches potentially as much as 30%, according to The Register. This means if a server has the capacity to support 100 users, this could drop to 70 after the software updates are applied.

Exploiting the flaw could allow attackers access to the core or kernel of operating systems, which is why it needs to be addressed by an update of any operating system running on any computer using the affected Intel chips, but computers using processers made by advanced micro devices (AMD) are not affected.

In an email to the Linux kernel mailing list, AMD said its chips are not affected because “the AMD microarchitecture does not allow memory references, including speculative references, that access higher privileged data when running in a lesser privileged mode when that access would result in a page fault”.

The severity of the security flaw in the Intel chips also means operating system updates should be applied as soon as they are available because the kernel typically contains confidential data such as passwords, login keys and files cached from disk, which could be useful to attackers.

Access to the kernel also means attackers could potentially disable any security functions and execute malicious code, The Telegraph reports.

Although Intel has not commented on the flaw publically, the chip maker has reportedly warned software suppliers such as Microsoft, Amazon and Apple. More details of the flaw are expected to be made public once software suppliers have issued security updates.

The security updates to make the kernel inaccessible to any software outside the operating system are expected within a week.

Only once these updates have been applied will the exact performance impact for specific Intel chips, operating systems and applications become clear.

News of the Intel chip security flaw has led to a surge in the share price of rival AMD, according to Bloomberg. AMD shares reportedly surged as much as 6.2% to $11.66 in early trading on 3 January, while Intel fell 2% to $45.90.