Title: SmarterTools SmarterMail < Build 9518 Unauthenticated background-of-the-day Path Coercion Severity: MEDIUM Date: January 28, 2026 CVE ID: CVE-2026-25067 CWE ID: CWE-706 Use of Incorrectly-Resolved Name or Reference CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N References: - SmarterMail Release Notes Credit: Cale Black of VulnCheck Description: - SmarterTools SmarterMail versions prior to build 9518 contain an unauthenticated path coercion vulnerability in the background-of-the-day preview endpoint. - The application base64-decodes attacker-supplied input and uses it as a filesystem path without validation. - On Windows systems, this allows UNC paths to be resolved, causing the SmarterMail service to initiate outbound SMB authentication attempts to attacker-controlled hosts. - This can be abused for credential coercion, NTLM relay attacks, and unauthorized network authentication.