CVE-2026-103903

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.

CVSS v3 8.8 HIGH

8.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/
https://cvd.cert.lv/disclosed/vuln-all-709639748
https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352
https://mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5

Configurations

No configuration.

History

12 Oct 2026, 11:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-12 11:17

Updated : 2026-10-16 17:25

NVD link : CVE-2026-103903

Mitre link : CVE-2026-103903

CVE.ORG link : CVE-2026-103903

JSON object : View

Products Affected

No product.

CWE

CWE-863

Incorrect Authorization

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