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CVE-2026-24423

SmarterTools SmarterMail Missing Authentication for Critical Function

9.8 CRITICALActively exploited (CISA KEV)Used in ransomwareEPSS 88.2%
  1. Published23 Jan 2026
  2. Added to CISA KEV5 Feb 2026
  3. Remediation due26 Feb 2026
Actively exploited (CISA KEV)

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.

Added to KEV: 5 Feb 2026Federal remediation due: 26 Feb 2026Used in ransomware

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 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Smartertools Smartermail< 100.0.9511

Remediation

Fixed in
Smartertools Smartermail≥ 100.0.9511

References

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Frequently asked

Is CVE-2026-24423 being actively exploited?

Yes. CVE-2026-24423 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 5 Feb 2026. It has been used in ransomware campaigns.

How severe is CVE-2026-24423?

CVE-2026-24423 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 88.2% probability of exploitation.

Which products are affected by CVE-2026-24423?

Affected products include Smartertools Smartermail.

How do I fix CVE-2026-24423?

Upgrade affected software to a fixed version, for example Smartertools Smartermail 100.0.9511 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-24423 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.