CVE-2025-52691
Smartertools Smartermail ≤ 100.0.9413
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HSummary
CVE-2025-52691 is a critical-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Smartertools Smartermail. Its CVSS base score is 10.0 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 0.3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SI-3 (Malicious Code Protection) and CM-7 (Least Functionality) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2025-52691 is a critical vulnerability (CVSS 10.0, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) affecting SmarterMail, a mail server software. It stems from CWE-434 (Unrestricted Upload of File with Dangerous Type), where successful exploitation allows an unauthenticated attacker to upload arbitrary files to any location on the server, potentially leading to remote code execution. The vulnerability was published on 2025-12-29.
An unauthenticated attacker with network access can exploit this vulnerability with low complexity and no user interaction required. By uploading malicious files to arbitrary server locations, the attacker can achieve high confidentiality, integrity, and availability impacts, including full remote code execution in a scoped manner.
Advisories from the Cyber Security Agency of Singapore (CSA) at https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2025-124/, WatchTowr Labs GitHub analysis at https://github.com/watchtowrlabs/watchTowr-vs-SmarterMail-CVE-2025-52691?ref=labs.watchtowr.com, and CISA's Known Exploited Vulnerabilities Catalog at https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-52691 provide further details on exploitation and mitigation recommendations.
This vulnerability is listed in CISA's Known Exploited Vulnerabilities Catalog, indicating active real-world exploitation.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-205544
Vulnerability Data
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.
- CWE(s)
- KEV Date Added
- 26 January 2026
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.1.1
Mitigating Controls (NIST 800-53 r5) AI
Malicious-code protection at entry points blocks dangerous file types from being accepted and executed.
Least functionality restricts the file types and automatic processing capabilities the system will accept.
Mobile-code controls define, authorize, and block unacceptable uploaded code before automatic processing occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.
Hardened configuration baselines can enforce allowed file types and processing rules.
Secure development practices include input validation and file-type restrictions that prevent this weakness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Configuration and acceptance testing verify that file-upload handling enforces allowed types and does not permit dangerous content to be stored or executed.
Secure-coding guidelines and security testing explicitly address restrictions on allowed file types and upload handling, reducing the risk that dangerous file uploads are accepted without validation.
Mandated testing for malicious content and known vulnerabilities reduces the likelihood that an outsourced component will contain or accept dangerous file types that could later be uploaded or executed.
Application allow-listing and pre-use scanning of received files directly blocks the introduction of executable content that has not been vetted, eliminating the primary vector for unrestricted dangerous file uploads.