CVE-2026-53904
Received Received - Intake

Account Denial of Service in MCO due to flawed password reset

Publication date: 2026-07-01

Last updated on: 2026-07-01

Assigner: CERT.PL

Description
MCO is vulnerable to Account Denial of Service due to improper implementation of password reset functionality. Each password reset request invalidates previously set password as well as previously issued temporary passwords, furthermore, password resets are not limited in any way. An attacker who provides victim's email and answer to their security question, can successfully initiate the reset process and continuously invalidate credentials, effectively locking the victim out of their account. Answering security questions has a limited number of tries which lowers the risk of this vulnerability. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.

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Meta Information

Published
2026-07-01
Last Modified
2026-07-01
Generated
2026-07-01
AI Q&A
2026-07-01
EPSS Evaluated
N/A
NVD
CVE-2026-53904
EUVD
EUVD-2026-40950

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
mco account to 25.3.3.1 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-640 The product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak.
CWE-307 The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.

Attack-Flow Graph

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Executive Summary

This vulnerability in MCO is an Account Denial of Service caused by improper implementation of the password reset functionality.

When a password reset request is made, it invalidates the previously set password and any temporary passwords. However, there is no limit on how many times password resets can be requested.

An attacker who knows the victim's email and can answer their security question can repeatedly initiate password resets, continuously invalidating the victim's credentials and effectively locking them out of their account.

The security questions have a limited number of tries, which somewhat reduces the risk, but the vulnerability still allows for account lockout through repeated resets.

Impact Analysis

This vulnerability can impact you by allowing an attacker to lock you out of your account.

By repeatedly initiating password resets, an attacker can invalidate your current password and temporary passwords, preventing you from accessing your account.

This results in a denial of service at the account level, disrupting your ability to use the affected service.

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