SmarterTools flaws being used in attacks

CISA lists 3 flaws in SmarterTools products as being used in attacks, most recently on 5 Feb 2026. All have been used in ransomware.

What to do

1. Update every SmarterTools product you use.Install the updates SmarterTools offers, on every device, and restart when asked. Each flaw below has a fix or clear advice; that’s one of CISA’s conditions for listing it.
2. If someone looks after IT for you, send them this page.Many of these are in equipment you don’t see: routers, firewalls, servers, the office network. Ask them to confirm each one is fixed, or that you don’t use the product.
3. Check anything else in the lookup.Search any app, company or CVE. Not being on CISA’s list doesn’t mean safe: keep updating either way.

Every flaw, newest first

1. Being used in attacksUsed in ransomwareAdded by CISA on 5 Feb 2026
   SmarterTools SmarterMail
   CVE-2026-24423SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability
   SmarterTools SmarterMail contains a missing authentication for critical function vulnerability in the ConnectToHub API method. This could allow the attacker to point the SmarterMail instance to a malicious HTTP server which serves the malicious OS command and could lead to command execution.
   CISA’s required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
   CVE recordNVD
2. Being used in attacksUsed in ransomwareAdded by CISA on 26 Jan 2026
   SmarterTools SmarterMail
   CVE-2026-23760SmarterTools 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.
   CISA’s required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
   CVE recordNVD
3. Being used in attacksUsed in ransomwareAdded by CISA on 26 Jan 2026
   SmarterTools SmarterMail
   CVE-2025-52691SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability
   SmarterTools SmarterMail contains an unrestricted upload of file with dangerous type vulnerability that could allow an unauthenticated attacker to upload arbitrary files to any location on the mail server, potentially enabling remote code execution.
   CISA’s required actionApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
   CVE recordNVD

From CISA’s Known Exploited Vulnerabilities catalog, updated 21 Oct 2026 (version 2026.10.21). CISA’s required actions are written for US government agencies. SmarterTools on CISA’s site.