Arbitrary file upload in SmarterMail - CVE-2025-52691
Published: January 14, 2026 / Updated: May 22, 2026
Vulnerability identifier: #VU121467
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2025-52691
CWE-ID: CWE-434
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerability details
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to insufficient validation of file during file upload. A remote attacker can upload a malicious file and execute it on the server.
Affected software
SmarterMail
How to mitigate CVE-2025-52691
Install updates from vendor's website.
SmarterMail - update to 100.0.9413
Links to Public Exploits and PoC-codes
- Exploit #12733 - CVE-2025-52691-poc (May 22, 2026)
- Exploit #12365 - CVE-2025-52691-PoC-SmarterMail-authentication-bypass-exploit-WT-2026-0001 (CVE-2025-52691 PoC: Based on watchtowr's article WT-2026-0001 about an authentication bypass exploit, this one is a functional Python attack script.) (February 6, 2026)
- Exploit #12354 - CVE-2025-52691-APT-PoC (February 6, 2026)
- Exploit #12335 - SmarterTools SmarterMail GUID File Upload Vulnerability (January 22, 2026)
- Exploit #12301 - watchTowr-vs-SmarterMail-CVE-2025-52691 (January 16, 2026)
- Exploit #12296 - CVE-2025-52691 (This repository contains a safe Proof of Concept (PoC) to detect vulnerable SmarterMail versions affected by CVE‑2025‑52691. The script performs version detection only and does not exploit the vulnerability.) (January 14, 2026)