It's tagged as a rumor, but you can rest assured it'll become a fact. Keep an eye out on your Tuesday patches, and apply them. According to Krebs On Security, Microsoft is about to release info on an extremely critical vulnerability in Windows. 

Rumors are indicative that the issue is to be found in a cryptographic component, which is present in all Windows versions. A patch would be released starting today, Tuesday. Not much is known about the alleged vulnerability, except that it would be the CryptoAPI.

- Krebs - 

Sources tell KrebsOnSecurity that Microsoft Corp. is slated to release a software update on Tuesday to fix an extraordinarily serious security vulnerability in a core cryptographic component present in all versions of Windows. Those sources say Microsoft has quietly shipped a patch for the bug to branches of the U.S. military and to other high-value customers/targets that manage key Internet infrastructure, and that those organizations have been asked to sign agreements preventing them from disclosing details of the flaw prior to Jan. 14, the first Patch Tuesday of 2020.

According to sources, the vulnerability in question resides in a Windows component known as crypt32.dll, a Windows module that Microsoft says handles “certificate and cryptographic messaging functions in the CryptoAPI.” The Microsoft CryptoAPI provides services that enable developers to secure Windows-based applications using cryptography, and includes functionality for encrypting and decrypting data using digital certificates.

A critical vulnerability in this Windows component could have wide-ranging security implications for a number of important Windows functions, including authentication on Windows desktops and servers, the protection of sensitive data handled by Microsoft’s Internet Explorer/Edge browsers, as well as a number of third-party applications and tools.

Equally concerning, a flaw in crypt32.dll might also be abused to spoof the digital signature tied to a specific piece of software. Such a weakness could be exploited by attackers to make malware appear to be a benign program that was produced and signed by a legitimate software company. This component was introduced into Windows more than 20 years ago — back in Windows NT 4.0. Consequently, all versions of Windows are likely affected (including Windows XP, which is no longer being supported with patches from Microsoft).

Microsoft responded, saying that it does not discuss the details of reported vulnerabilities before an update is available. And that is the good news, a patch will be in place real soon.

Source: Krebs On Security via HWI

Rumor: Microsoft might share information on extremely critical vulnerability later today