Unauthenticated RCE in SmarterTools SmarterMail ConnectToHub API
CVE-2026-24423 is a critical unauthenticated remote code execution vulnerability in SmarterTools SmarterMail affecting versions prior to build 9511. The flaw is in the ConnectToHub API method and is described as a missing authentication check for a critical function. A remote attacker can invoke ConnectToHub without valid credentials and direct the SmarterMail instance to connect to an attacker-controlled HTTP server. That server can then supply a malicious operating system command, which the vulnerable application executes on the SmarterMail host.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
Repository purpose: a minimal proof-of-concept to reproduce CVE-2026-24423 in SmarterMail’s ConnectToHub workflow by standing up an attacker-controlled “Hub” HTTP service and then triggering the victim’s unauthenticated connect-to-hub API so the victim SSRFs to the hub and consumes a malicious JSON response. Structure: - CVE-2026-24423.py: Python3 HTTP server (http.server) that listens on 0.0.0.0:80 and only responds to POST /web/api/node-management/setup-initial-connection. It logs the received request body and returns a crafted JSON object containing fields like ClusterID/SharedSecret and, critically, SystemMount with MountPath "C:\\" and CommandMount "whoami > C:\\whoami.txt". This models the trust-boundary violation where the victim treats hub-provided configuration as authoritative and performs system-level actions. - README.md: Explains the vulnerability chain (unauthenticated admin interface + SSRF to attacker hub + hub response used for local operations → potential RCE). Provides a sample request to POST /api/v1/settings/sysadmin/connect-to-hub with hubAddress pointing to the attacker server. Exploit capabilities: - Acts as the attacker-controlled hub endpoint to deliver a malicious configuration payload. - Demonstrates a command-execution outcome (example Windows command writing whoami output to C:\\whoami.txt) if the target is vulnerable. Notes: - This repo does not include an automated client to send the trigger request; it relies on manual tooling (Burp/Yakit) per README. - The payload is hardcoded and Windows-oriented (C:\\ paths, cmd redirection).
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
92 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A referenced SmarterMail ConnectToHub remote code execution vulnerability/template.
An unauthenticated remote code execution vulnerability in SmarterTools SmarterMail via the ConnectToHub API, where missing authentication allows remote attackers to trigger OS command execution.
A second SmarterMail vulnerability (described as a critical RCE bug in the article) that CISA warns is under active exploitation and can also lead to full system compromise.
SmarterMail unauthenticated RCE in the ConnectToHub API (pre-build 9511).
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.