CVE-2026-24423

CriticalActively exploited (CISA KEV)Known to be used in ransomware campaigns

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.

SeverityCritical

CVSS9.8

Exploit probability—

ProductSmarterTools SmarterMail

PublishedJan 23, 2026

First seenJan 23, 2026

Added to KEVFeb 5, 2026

Weakness typeCWE-306Missing authentication for critical function

How to fix

CISA 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.

CISA due date: Feb 26, 2026

Update

smartertools smartermail100.0.9511 or later

Patches

smartertools.com/smartermail/release-notes/current

Affected products

Product	Affected versions	Fixed in
smartertools smartermail	v < 100.0.9511	100.0.9511

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

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