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CVE-2026-23760: SmarterTools SmarterMail Authentication Bypass Using an Alternate Path or Channel Vulnerability

CVE-2026-23760 is rated critical with a CVSS v3.1 base score of 9.8 and affects SmarterTools SmarterMail. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-01-26, which means exploitation in the wild has been observed.

Vulnerability description

SmarterTools SmarterMail versions prior to build 9511 contain an authentication bypass vulnerability in the password reset API. The force-reset-password endpoint permits anonymous requests and fails to verify the existing password or a reset token when resetting system administrator accounts. An unauthenticated attacker can supply a target administrator username and a new password to reset the account, resulting in full administrative compromise of the SmarterMail instance. NOTE: SmarterMail system administrator privileges grant the ability to execute operating system commands via built-in management functionality, effectively providing administrative (SYSTEM or root) access on the underlying host.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

• Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
• Attack complexity: Low. No special conditions; the attack can be repeated reliably.
• Privileges required: None. No account or prior access is needed.
• User interaction: None. No action from any user is needed.
• Scope: Unchanged. Impact stays within the vulnerable component.
• Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
• Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
• Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-288: Authentication Bypass Using an Alternate Path or Channel

The product requires authentication, but the product has an alternate path or channel that does not require authentication.

Affected products

• Smartertools Smartermail: before 100.0.9511

References

• https://code-white.com/public-vulnerability-list/#authenticationserviceforceresetpassword-missing-authentication-in-smartermail
• https://labs.watchtowr.com/attackers-with-decompilers-strike-again-smartertools-smartermail-wt-2026-0001-auth-bypass/
• https://www.vulncheck.com/advisories/smartertools-smartermail-authentication-bypass-via-password-reset-api
• https://www.huntress.com/blog/smartermail-account-takeover-leading-to-rce
• https://www.smartertools.com/smartermail/release-notes/current
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-23760