# CVE-2026-67279: SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS

> CVE-2026-67279: SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS. CVSS 6.5 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2026-67279
Last updated: 2026-09-26T04:17:47Z

- Published: 2026-09-05 20:00 UTC · Updated: 2026-09-26 04:17 UTC · Assigner: CERT-PL
- CVSS: 6.5 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- EPSS: 2.3%, 83th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2026-09-25, federal due date 2026-09-28, ransomware use: Unknown
- CWE: CWE-841

## Description

RouterOS SSH enters the connection protocol after a client-requested rekey even though user authentication was never attempted, allowing an unauthenticated client to open a session channel and send an exec request. On affected builds the server dispatches the command, enabling unauthenticated creation, overwrite, and reconstruction of files in the RouterOS managed file namespace, including support files containing configuration and diagnostic data.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

## CISA required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

## Affected vendors and products

- Mikrotik: RouterOS

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-67279)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-67279)
- [https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve](https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve)
- [https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/](https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/)
- [https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802](https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802)
- [https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801](https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801)
- [https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800](https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800)
- [https://mikrotik.com/supportsec/september-2026-vulnerability/](https://mikrotik.com/supportsec/september-2026-vulnerability/)
- [https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/](https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-67279 · Markdown: https://rewindex.com/cve/CVE-2026-67279.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-67279 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:16:41.931Z