CVE-2026-67279

Mikrotik RouterOS Improper Enforcement of Behavioral Workflow

6.5 MEDIUMActively exploited (CISA KEV)Public exploitEPSS 1.03%

Published5 Sept 2026
Added to CISA KEV25 Sept 2026
Remediation due28 Sept 2026

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)

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityLow

IntegrityLow

AvailabilityNone

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

Affected products

Mikrotik Routeros≥ 6.0 < 6.49.21 · ≥ 7.0 < 7.23.4 · ≥ 7.24 < 7.24.2

Remediation

Fixed in

Mikrotik Routeros≥ 6.49.21

Patch & vendor advisories

https://mikrotik.com/supportsec/september-2026-vulnerability/

References

https://bishopfox.com/blog/mikrotrick-inside-the-routeros-takeover-chainThird Party Advisory
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/MitigationThird Party 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://mikrotik.com/supportsec/september-2026-vulnerability/Vendor Advisory
https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ExploitThird Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67279US Government Resource

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-67279 being actively exploited?

Yes. CVE-2026-67279 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 25 Sept 2026.

How severe is CVE-2026-67279?

CVE-2026-67279 has a CVSS 3.1 base score of 6.5, rated medium. EPSS estimates a 1.03% probability of exploitation.

Which products are affected by CVE-2026-67279?

Affected products include Mikrotik Routeros.

How do I fix CVE-2026-67279?

Upgrade affected software to a fixed version, for example Mikrotik Routeros 6.49.21 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-67279 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.