CVE-2025-52691
SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 16 February 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
Successful exploitation of the vulnerability could allow an unauthenticated attacker to upload arbitrary files to any location on the mail server, potentially enabling remote code execution.
- CVSS 3.1
- 10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 85.66% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 26 January 2026 · due 16 February 2026 · used in ransomware campaigns
- Weakness
- CWE-434
- Affected
- smartertools/smartermail
- Source
- 5f57b9bf-260d-4433-bf07-b6a79e9bb7d4
EPSS 85.7% since 30 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://www.smartertools.com/smartermail/release-notes/current ; https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2025-124/ ; https://nvd.nist.gov/vuln/detail/CVE-2025-52691
References
- https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2025-124/Third Party Advisory
- https://github.com/watchtowrlabs/watchTowr-vs-SmarterMail-CVE-2025-52691?ref=labs.watchtowr.comExploit, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-52691US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.