CVE-2026-67279SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS
Updated under an hour ago ()
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It affects Mikrotik RouterOS. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Sep 25, 2026; federal agencies had to remediate by Sep 28, 2026. Treat that date as your deadline.
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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)
- CVSS
- 6.9 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-841
- Known exploited
- Added to CISA KEV Sep 25, 2026; federal remediation due Sep 28, 2026Apply 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.
- EPSS (exploitation in the next 30 days)
- 1.03% (percentile 63)
- Assigned by
- CERT-PL
- NVD analysis
- Analyzed
- Record last updated
- Sep 26, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mikrotik RouterOS mikrotik:routeros (from the name) | from 7.24 before 7.24.2; from 7.0.0 before 7.23.4; from 6.0.0 before 6.49.21 | CNA record |
mikrotik routeros mikrotik:routeros | from 6.0 before 6.49.21; from 7.0 before 7.23.4; from 7.24 before 7.24.2 | NVD |
References
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cvethird-party-advisory
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/technical-description, mitigation, third-party-advisory
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/exploit, third-party-advisory
- https://mikrotik.com/supportsec/september-2026-vulnerability/vendor-advisory
- https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802release-notes
- https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801release-notes
- https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800release-notes
- https://bishopfox.com/blog/mikrotrick-inside-the-routeros-takeover-chainthird-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67279us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.