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Vulnerability · Published Oct 12, 2026 · Assigned by ENISA

CVE-2026-103903MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation

High 8.8

In plain English

A high-severity incorrect authorization in RouterOS from MikroTik. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.4%top 64.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
MikroTik RouterOS 7.0.0 – before 7.24.5

Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References