How severe is CVE-2026-24423?

CVE-2026-24423 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-24423 being actively exploited?

Yes. CVE-2026-24423 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-02-05, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2026-24423?

CVE-2026-24423 affects Smartertools Smartermail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-24423?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2026-24423 have an EU (EUVD) identifier?

Yes. CVE-2026-24423 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-4273. It is also flagged as exploited in the EUVD (since 2026-02-05).

When was CVE-2026-24423 published?

CVE-2026-24423 was published on 2026-01-23 and last updated on 2026-08-04.

CVE-2026-24423

CVE-2026-24423 is a critical-severity vulnerability in Smartertools Smartermail with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-02-05). The underlying weakness is classified as CWE-306.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 9.3
EPSS exploit prediction: 88% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2026-02-05)
EU (EUVD) id: EUVD-2026-4273
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2026-02-05)
Weakness: CWE-306
Affected product: Smartertools Smartermail
Published: 2026-01-23
Last modified: 2026-08-04

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.

Frequently asked questions

What is CVE-2026-24423?: 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.
How severe is CVE-2026-24423?: CVE-2026-24423 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-24423 being actively exploited?: Yes. CVE-2026-24423 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-02-05, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2026-24423?: CVE-2026-24423 affects Smartertools Smartermail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-24423?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2026-24423 have an EU (EUVD) identifier?: Yes. CVE-2026-24423 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-4273. It is also flagged as exploited in the EUVD (since 2026-02-05).
When was CVE-2026-24423 published?: CVE-2026-24423 was published on 2026-01-23 and last updated on 2026-08-04.

References

Affected products (1)

cpe:2.3:a:smartertools:smartermail:*:*:*:*:*:*:*:*

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