What’s Vulnerable › Vulnerabilities

CVE-2026-104082: SmarterMail < Build 9777 SysAdmin Remote Code Execution via Volume Mount

• Severity: high (CVSS 7.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-09 · updated 2026-10-27
• Weakness: CWE-94

Description

SmarterMail before build 9777 contains a remote code execution vulnerability that allows an attacker holding a SysAdmin-scoped access token to bypass the Volume Mount script-directory containment control by provisioning a new mail domain with an arbitrary FileStore root path inside the trusted Scripts directory via the domain-put endpoint. Attackers can disclose the Scripts path through the AddOrUpdateMount endpoint, clear the upload extension blacklist via the global-mail endpoint, then upload a malicious script through the ordinary mail file-storage upload API so that saving a CommandMount triggers RunScript before validation, resulting in a reverse shell executing as the SmarterMail service account with SYSTEM-level privileges.

Affected products

• SmarterTools SmarterMail: before Build 9777 — fixed in Build 9777

How to fix

Upgrade to a fixed version: SmarterTools SmarterMail Build 9777. Check the vendor advisory for mitigations.

References

• https://blog.evan.lat/posts/sm/
• https://www.smartertools.com/smartermail/release-notes/current#/9526:~:text=Build%209777%20(Oct%208%2C%202026)
• https://www.vulncheck.com/advisories/smartermail-build-9777-sysadmin-remote-code-execution-via-volume-mount

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