Known exploited vulnerability
CVE-2026-24423
The short answer
CVE-2026-24423 affects SmarterTools SmarterMail and is rated critical (CVSS 9.3). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-02-05: attackers are using it, so patch it first.
What it is
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.
Weakness: CWE-306.
Severity
9.3 critical
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Exploited (CISA KEV)
Yes, since Feb 5, 2026
Federal due date Feb 26, 2026
EPSS, next 30 days
88%
Higher than 100% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
What CISA says to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected products
SmarterMail. NVD's record lists the exact affected versions.
References
- code-white.com/public-vulnerability-list/#systemadminsettingscontrollerconnecttohub-missing-authentication-in-smartermail Third Party Advisory
- www.smartertools.com/smartermail/release-notes/current Release Notes
- www.vulncheck.com/advisories/smartertools-smartermail-unauthenticated-rce-via-connecttohub-api Third Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-24423 US Government Resource
Questions
Is CVE-2026-24423 being exploited?
Yes. CISA added CVE-2026-24423 to its Known Exploited Vulnerabilities catalog on 2026-02-05, with a federal remediation due date of 2026-02-26. CISA lists it as used in ransomware campaigns.
How do I fix CVE-2026-24423?
CISA's 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.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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