CVE-2026-24423: SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2026-02-05. EPSS: 88.2% chance of exploitation in the next 30 days.

SmarterTools SmarterMail versions prior to build 9511 contain an unauthenticated remote code execution vulnerability in the ConnectToHub API method. The attacker could point the SmarterMail to the malicious HTTP server, which serves the malicious OS command. This command will be executed by the vulnerable application.

Affected products

• SmarterTools SmarterMail: before 100.0.9511 (fixed in 100.0.9511)

Published 2026-01-23. Last modified 2026-08-04.