CVE-2026-24423
Published 2026-01-23 · Updated 2026-08-04 · Source disclosure@vulncheck.com
Summary
CVE-2026-24423 is a critical-severity (CVSS 9.8) vulnerability in SmarterTools SmarterMail. CISA added it to the Known Exploited Vulnerabilities catalog on February 5, 2026, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by February 26, 2026. CISA also lists it as known to be used in ransomware campaigns, so it should be prioritised accordingly. SmarterTools has 3 vulnerabilities in the KEV catalog, 3 of them linked to ransomware.
All 3 known-exploited SmarterTools vulnerabilities →Description
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.
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA Known-Exploited Vulnerability
Product: SmarterTools — SmarterMail
Name: SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability
Date added: 2026-02-05 · Due: 2026-02-26
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
References
- https://code-white.com/public-vulnerability-list/#systemadminsettingscontrollerconnecttohub-missing-authentication-in-smartermail
- https://www.smartertools.com/smartermail/release-notes/current
- https://www.vulncheck.com/advisories/smartertools-smartermail-unauthenticated-rce-via-connecttohub-api
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-24423