CVE-2026-67279: Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability

CISA Known Exploited Vulnerabilities

Name

Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability

Vendor

MikroTik

Product

RouterOS

Added to the catalog

2026-09-25

Due date for US federal agencies

2026-09-28

Weaknesses

CWE-841

Catalog version

2026.10.30

Mikrotik RouterOS contains an improper enforcement of behavioral workflow vulnerability that could allow an unauthenticated client to open a session channel and send an exec request. This vulnerability can be chained to achieve unauthenticated exploitation of CVE-2026-86060.

Required action (CISA)

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.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

• https://mikrotik.com/supportsec/september-2026-vulnerability
• https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
• https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
• https://nvd.nist.gov/vuln/detail/CVE-2026-67279

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2026-09-05T20:17:18.390

Last modified

2026-09-26T04:17:47.273

Weaknesses

CWE-841

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)

References

• https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve (Third Party Advisory)
• https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ (Mitigation, Third Party Advisory)
• https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 (Release Notes)
• https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 (Release Notes)
• https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 (Release 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/ (Exploit, Third Party Advisory)
• https://bishopfox.com/blog/mikrotrick-inside-the-routeros-takeover-chain (Third Party Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67279 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:42:31.494Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-67279

CVE record

Title (CNA)

SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS

Assigner

CERT-PL

State

PUBLISHED

Published

2026-09-05T20:00:57.894Z

Updated

2026-09-26T03:55:45.145Z

Problem types

CWE-841 Improper enforcement of behavioral workflow

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)

References

• https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve
• https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/
• https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/
• https://mikrotik.com/supportsec/september-2026-vulnerability/
• 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/7-24-2-stable-is-released/272800

Read on 2026-11-03T02:20:55.488Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/67xxx/CVE-2026-67279.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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