MikroTik RouterOS Flaw (CVE-2026-89035) Rated CVSS 9.1
A newly published critical vulnerability in MikroTik RouterOS carries a CVSS score of 9.1. Here is what is affected and how to respond.
Key points
- CVE-2026-89035 affects MikroTik RouterOS.
- CVSS 9.1 (Critical).
- No exploitation confirmed yet.
MikroTik RouterOS is affected by CVE-2026-89035, a security flaw that the National Vulnerability Database rates 9.1 out of 10.
At a glance
- CVE
- CVE-2026-89035
- Product
- MikroTik RouterOS
- CVSS
- 9.1 Critical
- Weakness
- CWE-613
- Exploited
- No known exploitation
What is the vulnerability?
The NVD entry states: 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.
Affected versions
| Vendor | Product | Versions |
|---|---|---|
| Mikrotik | RouterOS | up to 7.23.6, up to 7.24.5 |
Is it being exploited?
There is no public confirmation of exploitation at the time of publication. It does not appear in CISA's Known Exploited Vulnerabilities catalog. We will update this report if that changes.
What should you do?
- Identify whether the affected product and versions run in your environment.
- Apply the vendor update listed in the advisory as soon as it is available.
- Limit network exposure of the affected service until it is patched.
- Monitor the vendor advisory for updated guidance or exploitation reports.
What to do and how to stay safe: CVE-2026-89035
- Vulnerability severity scores ignore your specific architecture and context.
- Exploitability depends on network exposure and user behavior, not just code flaws.
- Prioritization requires continuous asset inventory and threat intelligence alignment.
Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.
Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-89035?
CVE-2026-89035 is a CWE-613 vulnerability in MikroTik RouterOS.
How severe is CVE-2026-89035?
It has a CVSS score of 9.1 Critical.
Is CVE-2026-89035 being exploited?
There is no public confirmation of exploitation at the time of publication.
