CVE-2026-104082: Code Injection (CVSS 7.2)

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.

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CVSS v3.1 Score

7.2

HIGH

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0061

Probability of exploitation

0.48%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-94 CWE-94

References

Other 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

Frequently Asked Questions

What is CVE-2026-104082? +

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. It has a CVSS v3.1 base score of 7.2 (HIGH).

How severe is CVE-2026-104082? +

CVE-2026-104082 has a CVSS v3.1 score of 7.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0061, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-104082? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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