SmarterTools SmarterMail contains a missing authentication for critical function vulnerability in the ConnectToHub API method. This could allow the attacker to point the SmarterMail instance to a malicious HTTP server which serves the malicious OS command and could lead to command execution.
SmarterTools ยท SmarterMail
Known ransomware use: Known
Follow the source advisory and validate exposure in your environment.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Recent reporting that mentions CVE-2026-24423.
Underground Telegram channels shared SmarterMail exploit PoCs and stolen admin credentials within days of disclosure. Flare explains how monitoring these communities reveals rapid weaponization of CVE-2026-24423 and CVE-2026-23760 tied to ransomware activity. [...]
The Cybersecurity & Infrastructure Security Agency (CISA) in the U.S. has issued a warning about CVE-2026-24423, an unauthenticated remote code execution (RCE) flaw in SmarterMail that is used in ransomware attacks. [...]