CVE-2025-52691: SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability

CISA Known Exploited Vulnerabilities

Name

SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability

Vendor

SmarterTools

Product

SmarterMail

Added to the catalog

2026-01-26

Due date for US federal agencies

2026-02-16

Weaknesses

CWE-434

Catalog version

2026.10.30

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.

Required action (CISA)

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

Ransomware use: CISA marks this vulnerability as known to be used in ransomware campaigns. CISA does not say which group used it.

Links in CISA's notes

• 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

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2025-12-29T03:15:42.837

Last modified

2026-10-07T12:10:00.170

Weaknesses

CWE-434

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.

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.com (Exploit, Third Party Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-52691 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:22.836Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2025-52691

CVE record

Title (CNA)

Upload Arbitrary Files

Assigner

CSA

State

PUBLISHED

Published

2025-12-29T02:15:58.200Z

Updated

2026-02-26T16:07:23.398Z

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.

References

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

Read on 2026-11-03T02:17:05.343Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2025/52xxx/CVE-2025-52691.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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