MikroTik RouterOS up to 7.24.4 WinBox Authentication Flow improper authorization

Summaryinfo

A vulnerability described as very critical has been identified in MikroTik RouterOS up to 7.24.4. This impacts an unknown function of the component WinBox Authentication Flow. Such manipulation leads to improper authorization. This vulnerability is documented as CVE-2026-103903. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in MikroTik RouterOS up to 7.24.4 and classified as very critical. Affected by this issue is an unknown code block of the component WinBox Authentication Flow. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality, integrity, and availability. CVE summarizes:

An incorrect authorization vulnerability in the WinBox authentication flow of MikroTik RouterOS allows a remote authenticated attacker with credentials for a low-privilege account permitted to use WinBox to obtain the authorization policy of a different existing account. The stage-one EC-SRP challenge and proof are verified using the attacker's account, while the independently supplied stage-two username is used to install the target account's privileges. By specifying a higher-privilege account such as admin, a low-privilege user can obtain a full administrative session without knowing the target account's password and can use that session to increase the privileges of the attacker's own account.

The advisory is shared for download at mikrotik.com. This vulnerability is handled as CVE-2026-103903 since 10/01/2026. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/12/2026). The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 7.24.5 or 7.25rc1 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Router Operating System

Vendor

• MikroTik

Name

• RouterOS

Version

• 7.24.0
• 7.24.1
• 7.24.2
• 7.24.3
• 7.24.4

License

• commercial

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Once again VulDB remains the best source for vulnerability data.

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