CVE-2026-24423
SmarterTools SmarterMail < Build 9511 Unauthenticated RCE via ConnectToHub API
- Critical 9.3
- Exploited: added to CISA KEV 5 Feb 2026
- 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.
Key facts
- Published
- 23 Jan 2026
- Last changed
- 4 Aug 2026
- Assigned by
- VulnCheck
- KEV added
- 5 Feb 2026
- KEV fix due
- 26 Feb 2026
- Used in ransomware
- Yes, according to CISA
- EPSS
- 88.177% likely to be exploited in the next 30 days, higher than 99.771% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: yes; Technical impact: total
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 9.3CVSS 4.0, Criticalfrom the CNA (VulnCheck)
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 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.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| SmarterTools | SmarterMail |
|
Timeline
- 23 Jan 2026 Published
- 5 Feb 2026 CVE-2026-24423 added to CISA KEV
- 5 Feb 2026 Added to the CISA KEV catalogue