CVE-2026-24423
Published: February 5, 2026
Official 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.
CISA KEV Advisory
SmarterTools SmarterMail Missing Authentication for Critical Function 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.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Risk Analysis
SmarterTools SmarterMail has a critical missing authentication vulnerability in its ConnectToHub API method, allowing an attacker to point the instance to a malicious HTTP server for command execution. With a CVSS score of 9.8 and a high EPSS score, this vulnerability is extremely severe and has a high likelihood of exploitation. Its inclusion in CISA's KEV catalog confirms active exploitation.
This vulnerability is actively exploited in the wild. It is remotely exploitable with low attack complexity and no user interaction required.
Administrators should apply available patches for SmarterTools SmarterMail immediately. Implement network segmentation and restrict access to the ConnectToHub API method.
Technical Analysis
CVE-2026-24423 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.
CISA has added CVE-2026-24423 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
News & Research Mentioning CVE-2026-24423
Underground Telegram channels shared SmarterMail exploit PoCs and stolen admin credentials within days of disclosure. Flare explains how monitoring these communities reveals rapid weaponization of CVE-2026-24423 and CVE-2026-23760 tied to ransomware activity. [...] [xlite_meta score:67 src:BleepingComputer xlite_fp:a06b6c12843d7762f64d13f5dfaf38050abc1a46aada007e4a8c8d1563aff19e]
CISA has added two new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2025-11953 React Native Community CLI OS Command Injection Vulnerability CVE-2026-24423 SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities established the KEV Catalog as a living list of known Common Vulnerabilities and Exposures (CVEs) that carry significant risk to the federal enterprise. BOD 22-01 requires Federal Civilian Executive Br [xlite_meta score:41 src:CISA Alerts xlite_fp:752a3871deb1a10aadd2d18cc359014979523214a02c99c0c010bc7b8f2eeddf]
All References (3)
Quick Facts
Known Threat Actors
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-24423 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1