How severe is CVE-2026-24423?

CVE-2026-24423 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-24423?

Affected package information for CVE-2026-24423 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-24423?

No fixed version has been published for CVE-2026-24423 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2026-24423 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-24423 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-24423?

CVE-2026-24423 has an EPSS (Exploit Prediction Scoring System) score of 83.4%, placing it in the 99th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2026-24423 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2026-24423 (SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-02-05. CISA required all US federal civilian agencies to remediate this vulnerability by 2026-02-26. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. This CVE has been used in known ransomware campaigns. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2026-24423?

CVE-2026-24423 is classified as Missing Authentication (CWE-306). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2026-24423?

CVE-2026-24423 affects smartertools smartermail. Check the affected-products list on this page against your deployed version to confirm exposure.

Is there exploit tooling available for CVE-2026-24423?

A Nuclei detection template exists for CVE-2026-24423, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2026-24423 published, and has it been updated?

CVE-2026-24423 was published on January 23, 2026 and was last updated on February 6, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-24423: Smartermail Missing Authentication (Critical 9.…

EPSS Exploitation Probability

via FIRST.org ↗

83.4%probability of exploitation in next 30 days

Very High Risk99th percentile+1.49%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

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.

Affected Products

1 product · 1 configurations

Application

smartermailsmartertools

< 100.0.9511

range

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is CVE-2026-24423 in your stack?

O3 detects CVE-2026-24423 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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