SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability

Critical Threat Advisory: This vulnerability is documented in active Ransomware campaigns. Immediate remediation required.

Technical Severity

CVSS v3.1 Metrics

CRITICAL

10 / 10

Minimal Risk Critical

Vector Specification

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

Exploitation Likelihood

EPSS Prediction

88.75 %

Predictive Probability

Percentile Rank

99.5 th

Documented as more likely to be exploited than 99.5% of known CVEs.

Detection Date

Jan 26, 2026

Remediation Due

Feb 16, 2026

CISA Catalog Active

Threat Analysis

SmarterTools SmarterMail contains an unrestricted upload of file with dangerous type vulnerability that could allow an unauthenticated attacker to upload arbitrary files to any location on the mail server, potentially enabling remote code execution.

Remediation Directive

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

External Intelligence

https://www.smartertools.com/smartermail/release-notes/current

https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2025-124/

NVD

National Vulnerability Database

https://nvd.nist.gov/vuln/detail/CVE-2025-52691