CVE-2019-1040

CVE-2019-1040 is a tampering vulnerability in Microsoft Windows that allows a man-in-the-middle attacker to bypass NTLM Message Integrity Check (MIC) protection, affecting various Windows versions including Windows 10, 7, 8.1, and multiple Server editions. The vulnerability has a CVSS score of 5.3 (MEDIUM) due to its high integrity impact, requiring user interaction and high attack complexity to exploit. While there is no known public exploit code or active exploitation listed in KEV, its high EPSS score (0.86185) and significant community discussion (6 mentions) and media coverage (6 articles) suggest considerable attention and potential for future exploitation, with some reports linking it to Chinese state-sponsored hacking. The vulnerability is addressed by hardening NTLM MIC protection on the server-side.