CVEs / CVE-2025-52691
CVE-2025-52691: SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability
- Known exploited in the CISA KEV catalog since 26 Jan 2026
- critical 10 CVSS 3.1 (from the CNA)
- EPSS 85.6% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
Are you affected? Check your servers with Stackurity: it lists the software on each server and the vulnerabilities to fix first.
Check your servers with Stackurity Already using Stackurity? Search for CVE-2025-52691
Summary
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.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| SmarterTools SmarterMail | SmarterMail versions Build 9406 and earlier | — |
Exploitation
| In CISA KEV since | 26 Jan 2026 |
|---|---|
| Due date for US federal agencies | 16 Feb 2026 |
| Used in ransomware campaigns | Known |
| Required action | Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. |
Severity
| CVSS 3.1 | 10 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HScored by the CNA (5f57b9bf-260d-4433-bf07-b6a79e9bb7d4) |
|---|---|
| Weakness | CWE-434 |
References
- CVE-2025-52691 on NVD
- CVE-2025-52691 in the CISA KEV catalog
- https://www.smartertools.com/smartermail/release-notes/current (cited by CISA)
- https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2025-124/ (cited by CISA)
- 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.com Exploit, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-52691 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.