Microsoft Security Response Center

**According to the CVSS metric, the attack vector is adjacent (AV:A). What does that mean for this vulnerability?** Exploiting this vulnerability requires an attacker to be within proximity of the target system to send and receive radio transmissions.

**According to the CVSS metric, privileges required is high (PR:H). What does that mean for this vulnerability?** The attacker must have access to the public encrypt key registered with the IDP(Entra ID) for successful exploitation.

**What type of information could be disclosed by this vulnerability?** An attacker who successfully exploited this vulnerability could potentially read small portions of heap memory.

**What privileges could be gained by an attacker who successfully exploited this vulnerability?** An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

**What type of information could be disclosed by this vulnerability?** An attacker who successfully exploited this vulnerability could potentially read small portions of heap memory.

**What privileges could be gained by an attacker who successfully exploited this vulnerability?** An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

**According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?** Successful exploitation of this vulnerability requires an attacker to prepare the target environment to improve exploit reliability.

**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.

**What privileges could be gained by an attacker who successfully exploited this vulnerability?** An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

**How can an attacker successfully exploit this vulnerability?** This vulnerability can be exploited when an attacker with admin privileges creates an x509 certificate with an MD5 property, which causes certificate validation to fail with no further validation checks.