Microsoft is preparing to release a pair of updates next Tuesday.
The company said in an advance notice that the November edition of the "Patch Tuesday" release will include one fix labeled "critical" and a second labeled "important."
The critical fix addresses a vulnerability in the Microsoft XML Core Services component in Windows 2000, XP, Server 2003, 2008 and Windows Vista. While Microsoft did not disclose the exact nature of the vulnerability, the company said that if exploited it could allow an attacker to remotely execute code on a targeted system.
While the second flaw could also allow an attacker to remotely execute code, Microsoft rated the issue as an "important" risk. The vulnerability lies within a component in Windows 2000, XP, Server 2003, Server 2008 and Windows Vista.
Microsoft offered little more on the nature of the vulnerability. The company typically refrains from disclosing specific details on a flaw until a fix can be released.
The November update comes just two weeks after the disclosure and patching of another critical vulnerability in a Windows component. Shortly after the company posted the fix, an attack for the flaw was reported.
Microsoft is planning to release the update next Tuesday. The update is typically released by early afternoon US Pacific time.