A crucial authentication bypass vulnerability in SmarterTools SmarterMail is actively being exploited within the wild by attackers, in accordance with safety researchers at watchTowr Labs.
The vulnerability, tracked as WT-2026-0001, permits unauthenticated attackers to reset the system administrator password with none validation, main to finish system takeover.
The flaw exists within the ForceResetPassword API endpoint, which is designed to deal with official password reset situations.
Nevertheless, the endpoint is uncovered with out authentication and comprises a crucial design flaw: it accepts a user-controlled parameter, IsSysAdmin, that branches the code logic to totally different password reset procedures.
smartermail launch notes ( supply : watchtowr labs)
When an attacker units IsSysAdmin to “true,” the appliance makes an attempt to reset the password of an administrator account. Critically, the implementation fails to validate the present password earlier than permitting the reset.
That’s carried out for normal person accounts however mysteriously omitted for directors; this inconsistency is the guts of the vulnerability.
The assault requires solely three items of knowledge despatched through a easy HTTP POST request:
The force-reset-password endpoint implicated in WT-2026-0001 ( supply: watchtowr labs)
The administrator username (generally “admin”), a brand new password of the attacker’s selecting, and the IsSysAdmin flag. The previous password discipline is ignored totally for admin accounts.
POST /api/v1/auth/force-reset-password HTTP/1.1
Host: xxxxxxx:9998
Content material-Sort: utility/json
Content material-Size: 145
{“IsSysAdmin”:”true”,
“OldPassword”:”watever”,
“Username”:”admin”,
“NewPassword”:”NewPassword123!@#”,
“ConfirmPassword”: “NewPassword123!@#”}
Lively Exploitation Confirmed
Patch diffing, the place attackers decompile safety patches to determine and perceive vulnerabilities, performed a key function on this risk.
SmarterMail launched model 9511 on January 15, 2026, simply six days after the vulnerability was found.
Full distant code execution achieved (supply: Watchtower Labs)
Attackers analyzed the patch, reverse-engineered the vulnerability, and commenced exploitation makes an attempt inside 48 hours of the discharge.
A SmarterMail discussion board publish from January 17 confirmed that exploitation makes an attempt had already occurred within the wild.
As soon as authenticated as an administrator, attackers achieve entry to a built-in function that amplifies the affect: The flexibility to create quantity mounts with arbitrary working system instructions.
These instructions execute with SYSTEM-level privileges, offering full distant code execution on the server.
PoC reaching a SYSTEM-level shell (supply: watchtowr labs)
This two-stage assault chain, which bypasses authentication after which executes instructions by official administrative options, transforms a password reset flaw into a whole system compromise.
WatchTowr Labs advises organizations utilizing SmarterMail to improve instantly to model 9511.
The patch provides correct password validation to the administrator reset path, stopping the exploit. Delaying this replace exposes methods to lively risk actor campaigns looking for susceptible situations.
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