CVE-2026-24423: SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 13 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 88.2%
EPSS score, percentile 99.8 of all scored records
- How severe?
- 9.3 Critical
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA deadline . Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Which versions are affected?
Affected
- before 100.0.9511
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
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 for this action: .
Advisories and patches
Linked from CISA's catalog entry
- https://www.smartertools.com/smartermail/release-notes/current
- https://www.cve.org/CVERecord?id=CVE-2026-24423
- https://nvd.nist.gov/vuln/detail/CVE-2026-24423
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 100.0.9511 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2026-24423 to its Known Exploited Vulnerabilities (KEV) catalog on 5 Feb 2026.
- CISA marks it as known to be used in ransomware campaigns.
- The due date CISA sets for the required action is 26 Feb 2026.
- The CVE record was published on 23 Jan 2026, 13 days before it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 9.3 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 88.2% (percentile 99.8), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
SmarterTools SmarterMail < Build 9511 Unauthenticated RCE via ConnectToHub API
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-306: Missing Authentication for Critical Function
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
More exploited SmarterTools vulnerabilities
- CVE-2025-52691: SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability
- CVE-2026-23760: SmarterTools SmarterMail Authentication Bypass Using an Alternate Path or Channel Vulnerability