This vulnerability is a heap-based buffer overflow in Microsoft Defender that permits an unauthorized attacker to execute arbitrary code. The weakness originates from insufficient bounds checking on heap allocations in the Defender engine, which can be triggered by receiving maliciously crafted data over the network. Successful exploitation would allow the attacker to gain control of local processes, potentially compromising confidentiality, integrity, and availability of the affected system.

Microsoft Malware Protection Engine is affected. No specific product versions are listed, so all deployments of the current Defender engine may be vulnerable until the patch is applied.

The CVSS score of 8.1 indicates a high severity of remote exploitation. No EPSS score is available, and the vulnerability is not listed in the CISA KEV catalog, suggesting it is not a current exploit target. The likely attack vector is over a network, inferred from the description that the overflow occurs when processing data received from the network. An attacker would need to deliver crafted input to the vulnerable component, and a successful payload could execute arbitrary code.