CVE-2026-89035

critical

Description

MikroTik RouterOS through 7.24.5 contains a session token replay vulnerability in the WebFig interface that allows attackers to bypass authentication by replaying captured session tokens across new ECDH sessions. The makeSessionKey function in libucrypto.so generates tokens using fixed salts without incorporating channel-specific or session-specific input, and the user service validates tokens against the login store without verifying channel context, enabling stolen tokens to grant persistent administrative access until the token store is explicitly cleared. This vulnerability extends the impact of CVE-2025-61481, which identified the underlying transport-layer exposure without a corresponding fix.

References

https://www.vulncheck.com/advisories/mikrotik-routeros-webfig-session-token-replay-authentication-bypass

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-107400

Details

Source: Mitre, NVD

Published: 2026-10-21

Updated: 2026-10-21

Risk Information

CVSS v2

Base Score: 7.1

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 7.4

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Severity: High

CVSS v4

Base Score: 9.1

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Severity: Critical