CVE-2026-103903 — MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation
An incorrect authorization vulnerability in the WinBox authentication flow of MikroTik RouterOS allows a remote authenticated attacker with credentials for a low-privilege accou…
Published: 2026-10-12 · CVSS: 8.7 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7