Microsoft is investigating a reported security flaw in its Office software suite that could allow hackers to remotely control users' systems.
The vulnerability has been described as “highly critical” by IT security company Secunia.
The reported hole cannot be patched with one of the eight security updates Microsoft made available to users this Tuesday, as part of its monthly patch release.
The alleged flaw exists in Microsoft's Jet Database Engine, which can be exploited to execute malicious code by encouraging users to open a specially designed .mdb file in Microsoft Access, said Secunia.
Secunia says exploit code for the flaw has already been made available on the internet.