CVE-2021-42980

CVE-2021-42980 describes a buffer overflow vulnerability in the IOCTL Handler 0x22001B of NoMachine Cloud Server versions above 4.0.346 and below 7.7.4. This flaw allows a local attacker to execute arbitrary code in kernel mode or trigger a denial of service through memory corruption and OS crashes using a specially crafted I/O Request Packet. With a CVSS score of 8.8 (High), the vulnerability has a local attack vector, low attack complexity, and high impact on confidentiality, integrity, and availability. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or inclusion in CISA's KEV catalog, though it has received some community discussion and media coverage.