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Actively exploitedKnown ransomware use

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

SmarterTools SmarterMail contains an authentication bypass using an alternate path or channel 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. This could allow an unauthenticated attacker to supply a target administrator username and a new password to reset the account, resulting in full administrative compromise of the SmarterMail instance.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 26 Jan 2026.
  • CISA lists it as known to be used in ransomware campaigns.
  • Rated Critical severity (CVSS 9.3, scored by Vendor).
  • Named in Cybergen threat actor reporting: Medusa.
  • It has been in the catalogue for 284 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

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.

Affected Versions

ProductVersions
SmarterTools SmarterMailbefore 100.0.9511

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for SmarterTools SmarterMail. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

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

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 16 Feb 2026 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

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CVE-2026-24423 · RansomwareSmarterTools SmarterMail Missing Authentication for Critical Function VulnerabilityAdded 5 Feb 2026CVE-2025-52691 · RansomwareSmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type VulnerabilityAdded 26 Jan 2026

All 3 exploited SmarterTools vulnerabilities

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2026-23760
  3. CVE record: CVE-2026-23760
  4. FIRST EPSS
  5. smartertools.com/smartermail/release-notes/current
  6. labs.watchtowr.com/attackers-with-decompilers-strike-again-smartertools-smartermail-wt-2026-0001-aut
  7. code-white.com/public-vulnerability-list/#authenticationserviceforceresetpassword-missing-authentica
  8. vulncheck.com/advisories/smartertools-smartermail-authentication-bypass-via-password-reset-api