Microsoft disclosed four actively exploited zero-day vulnerabilities being used to attack on-premises versions of Microsoft Exchange Server. The vulnerabilities identified are CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065, all of which affect Microsoft Exchange Server. Exchange Online is not affected. In the attacks observed, the threat actor used these vulnerabilities to access on-premises Exchange servers which enabled access to email accounts, and allowed installation of additional malware to facilitate long-term access to victim environments. Microsoft Threat Intelligence Center (MSTIC) attributes this campaign with high confidence to HAFNIUM, a group assessed to be state-sponsored and operating out of China, based on observed victimology, tactics and procedures.

ColdFusion versions 2023.6, 2021.12 and earlier are affected by an Improper Access Control vulnerability that could lead to arbitrary file system read. An attacker could leverage this vulnerability to bypass security measures and gain unauthorized access to sensitive files and perform arbitrary file system write. Exploitation of this issue does not require user interaction.