CVE-2026-67279
KEV: known exploited SSVC: activeSSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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
Attack conditions and impact
Derived from the NVD CVSS 3.1 vectorThis vulnerability may be exploitable over the internet without authentication or user interaction.
| Metric | Value | Meaning |
|---|---|---|
| Attack vector AV | N | Network |
| Attack complexity AC | L | Low (easy) |
| Privileges required PR | N | None |
| User interaction UI | N | None |
| Scope S | U | Unchanged |
| Confidentiality C | L | Low |
| Integrity I | L | Low |
| Availability A | N | None |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
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 KEV entry
Mikrotik RouterOS Improper Enforcement of Behavioral Workflow Vulnerability — MikroTik / RouterOS
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: 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.
https://mikrotik.com/supportsec/september-2026-vulnerability ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: 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
CVSS assessments
| Provider | Version | Score | Vector |
|---|---|---|---|
| NVD / [email protected] (Secondary) | 4.0 | 6.9 MEDIUM | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD / [email protected] (Primary) | 3.1 | 6.5 MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| CNA / CERT-PL | 4.0 | 6.9 MEDIUM | 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 |
Affected products and packages
CNA (CVE.org)
| Vendor | Product | Versions |
|---|---|---|
| Mikrotik | RouterOS | affected: 7.24 … < 7.24.2 affected: 7.0.0 … < 7.23.4 affected: 6.0.0 … < 6.49.21 default: unaffected |
NVD CPE (3)
Show CPE list
| Vendor | Product | Range | CPE |
|---|---|---|---|
| mikrotik | routeros | >= 6.0, < 6.49.21 | cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:* |
| mikrotik | routeros | >= 7.0, < 7.23.4 | cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:* |
| mikrotik | routeros | >= 7.24, < 7.24.2 | cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:* |
Linux distribution status
References (9)
- https://bishopfox.com/blog/mikrotrick-inside-the-routeros-takeover-chain NVD, ADP CISA-ADP Third Party Advisorythird-party-advisory
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve NVD, CNA Third Party Advisorythird-party-advisory
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ NVD, CNA MitigationThird Party Advisorytechnical-description
- https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 NVD, CNA Release Notesrelease-notes
- https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 NVD, CNA Release Notesrelease-notes
- https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 NVD, CNA Release Notesrelease-notes
- https://mikrotik.com/supportsec/september-2026-vulnerability/ NVD, CNA Vendor Advisoryvendor-advisory
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ NVD, CNA ExploitThird Party Advisoryexploit
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67279 NVD, ADP CISA-ADP US Government Resourcegovernment-resource