CVE-2024-0057

FAQ

What kind of security feature could be bypassed by successfully exploiting this vulnerability?

A security feature bypass vulnerability exists when Microsoft .NET Framework-based applications use X.509 chain building APIs but do not completely validate the X.509 certificate due to a logic flaw. An attacker could present an arbitrary untrusted certificate with malformed signatures, triggering a bug in the framework. The framework will correctly report that X.509 chain building failed, but it will return an incorrect reason code for the failure. Applications which utilize this reason code to make their own chain building trust decisions may inadvertently treat this scenario as a successful chain build. This could allow an adversary to subvert the app's typical authentication logic.

How could an attacker exploit this vulnerability?

An attacker could exploit this by creating a specially crafted X.509 certificate that intentionally introduce or intentionally induces a chain building failure.

Is there are reason for such a high CVSS score?

Yes, the CVSS scoring guide recommends using a reasonable worst-case implementation scenario when scoring vulnerabilities in software libraries. Vulnerabilites in .NET Framework and similar products are scored with this advice in mind. The score for your implmentation this product may not be as severe, however we recommend installing the update as soon as possible in an abundance of caution.

Please see the CVSS user guide for more information.