CVE-2021-20589

CVE-2021-20589 is a buffer access vulnerability affecting the communication drivers of various Mitsubishi GOT2000 series HMI models (GT27, GT25, GT23, GT21), GOT SIMPLE series GS21, GT SoftGOT2000, and Tension Controller LE7-40GU-L. A remote, unauthenticated attacker can exploit this flaw by sending specially crafted packets, leading to a denial of service by stopping the communication function of the affected products. The vulnerability has a CVSS v3.1 score of 7.5 (HIGH), indicating a severe impact. Its attack vector is network-based with low attack complexity, requiring no user interaction or privileges, and resulting in high availability impact (denial of service). Currently, there is no evidence of active exploitation, and no public exploit code (Metasploit, Nuclei, ExploitDB) is available. The vulnerability has received minimal community discussion and media coverage, suggesting a low level of public awareness or active threat.