CVE-2026-24423
CriticalExploitedPublic exploitSmarterTools SmarterMail < Build 9511 Unauthenticated RCE via ConnectToHub API
Published Jan 23, 2026 · Updated Aug 4, 2026
Key Facts
Patch immediately- CVE-2026-24423 is a critical-severity vulnerability (CVSS 9.3 v4) affecting SmarterMail (Smartertools).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jan 28, 2026 and is known to be used in ransomware campaigns. Public exploit code is available.
- EPSS estimates a 88% probability of exploitation in the next 30 days.
- Fixed versions are available, including SmarterMail 100.0.9511.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v4
9.3
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
EPSS (30-day exploit likelihood)
88%
Higher than 99.7% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings, used by ransomware
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2026-24423 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Feb 5, 2026 | Feb 26, 2026 | Known |
| Industry KEV feed | Jan 28, 2026 | Feb 26, 2026 | Known |
| CIRCL KEV | Feb 5, 2026 | Feb 26, 2026 | Known |
| ENISA EUVD | Feb 5, 2026 | n/a | Not reported |
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.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| SmarterMailSmartertools | See advisory | 100.0.9511 |
Patched Releases
SmarterMail
100.0.9511
Timeline
Publicly disclosed
Jan 23, 2026
Added to Industry KEV feed
Jan 28, 2026
Added to CISA KEV
Feb 5, 2026
Added to CIRCL KEV
Feb 5, 2026
Added to ENISA EUVD
Feb 5, 2026
Last updated
Aug 4, 2026
Weakness Type
- CWE-306 Missing Authentication for Critical Function
References
- advisoryhttps://code-white.com/public-vulnerability-list/#systemadminsettingscontrollerconnecttohub-missing-authentication-in-smartermail
- advisoryhttps://www.vulncheck.com/advisories/smartertools-smartermail-unauthenticated-rce-via-connecttohub-api
- patchhttps://www.smartertools.com/smartermail/release-notes/current
- exploitVulnCheck exploitation report
- otherhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-24423
FAQ
Common Questions.
SmarterTools SmarterMail versions prior to build 9511 contain an unauthenticated remote code execution vulnerability in the ConnectToHub API method.
Affected: SmarterMail (Smartertools). The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jan 28, 2026 and is known to be used in ransomware campaigns.
Yes. It was added on Feb 5, 2026 with a federal remediation due date of Feb 26, 2026.
Public exploit code is available.
Fixed versions are available, including SmarterMail 100.0.9511.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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