On 2026-02-05, CISA added CVE-2026-24423 (SmarterTools SmarterMail) to its Known Exploited Vulnerabilities (KEV) catalog [2]. The vulnerability is listed in the catalog as "SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability" [2]. CISA requires remediation in accordance with the listed vendor mitigation guidance; see the original text in the body for specific requirements [2].
Backfill: this event became public on Feb 5, 2026 and we added it on Nov 10, 2026. It is not a new event.
CISA Adds SmarterTools SmarterMail Vulnerability CVE-2026-24423 to Known Exploited Vulnerabilities Catalog
1 min read
- Disclosed
- Feb 5, 2026
- Published
- Nov 10, 2026
- Last updated
- Nov 8, 2026
- CVSS basis
- Our assessment
- 88.2%, higher than 100% of CVEs
- Exploitation and patch status
- ExploitedKEV
- Attack vector
- Vulnerability status
- Actor type
- Motivation
On this page
30-second summary
What happened
Who is affected
Industries mainly affected: Government, Cross-industry
What to do nowOur advice
CISA requires remediation in accordance with the listed vendor mitigation guidance; see the original text in the body for specific requirements [2].
Timeline
Technical details
CISA KEV Listing Record
CISA added CVE-2026-24423 (SmarterTools SmarterMail) to the Known Exploited Vulnerabilities () catalog on 2026-02-05 [2].
Original Technical Description
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. [2]
Official 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. [2]
Individual Vulnerability Record
The U.S. National Vulnerability Database (NVD) provides an independent vulnerability record and description for CVE-2026-24423 [1].
References
Official / primary3
- [1]
“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 vuln”
- [2]
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