Vulnerability in Mikrotik Routeros
CVE-2026-89035
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.
Published .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- www.vulncheck.com/advisories/mikrotik-routeros-webfig-session-token-replay-auth… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-89035?
- CVE-2026-89035 is a high-severity vulnerability in Mikrotik Routeros, classified under Insufficient Session Expiration. CVSS score: 7.4/10. Published 2026-10-21.
- How severe is CVE-2026-89035?
- High severity. CVSS v3 base score is 7.4 out of 10.