Background exploitation KEV catalog Ransomware No authentication
CVE-2026-23760

SmarterTools SmarterMail Authentication Bypass Using an Alternate Path or Channel Vulnerability

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…

CheckOps priority index
9.6/10 Patch within 24 h
Severity9.3
Probability9.6
Exploitation5/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 96.4% higher than 99.9% of CVEs
CVSS 4.0 9.3 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/
Exploited for 281 days 26 Jan 2026
CISA due date 16 Feb 2026 for US federal agencies

Exploitation probability EPSS · FIRST

05010025 Sep05 Oct15 Oct24 Oct02 Nov
EPSS probability (%)Percentile among all CVEs

Exploitation signals 5 / 5

  • KEV catalog (CISA)26 Jan 2026
  • Exploited in EUVD (ENISA)26 Jan 2026
  • Used by ransomwareyes
  • EPSS above 10 %96.4%
  • No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

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

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

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 products

SmarterMail
Affected versions
  • 0 <100.0.9511
Weaknesses (CWE)

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

  1. Published

  2. Exploitation reported (ENISA)

  3. Added to the KEV catalog

  4. CISA remediation due date

  5. EPSS peak: 96.5%

References

Other exploited vulnerabilities from the same vendor

  • CVE-2026-24423SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability
    9.4 · Background exploitation
  • CVE-2025-52691SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability
    9.6 · Background exploitation

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Sources: CISA KEV · ENISA EUVD · FIRST EPSS · OSV. Public data aggregated by CheckOps, updated automatically. Source texts remain the property of their authors. All exploited vulnerabilities