CVE-2026-24423 CRITICAL

CVE-2026-24423: SmarterTools SmarterMail < Build 9511 Unauthenticated RCE via ConnectToHub API

Vendor Smartertools

Product SmarterMail

Weakness CWE-306 · Missing auth

KEV Status Known Exploited

Ransomware Used in campaigns

Published January 23, 2026

Last update March 5, 2026

View on NVD All CVEs

CVSS base score

9.3/10

Attack vector Network

Attack complexity Low

Privileges required None

User interaction None

Confidentiality —

Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

What the vulnerability does

01Description

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.

CISA mandated remediation

02CISA 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.

Key dates

03Disclosure timeline

January 23, 2026 CVE published

March 5, 2026 Record updated

External resources

04References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-24423 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/306.html CISA KEV Reference https://www.smartertools.com/smartermail/release-notes/current CISA KEV Reference https://www.cve.org/CVERecord?id=CVE-2026-24423 CISA KEV Reference https://nvd.nist.gov/vuln/detail/CVE-2026-24423