CVE-2026-67279: CWE-841 Improper enforcement of behavioral workflow in Mikrotik RouterOS
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 v4.0
Score 6.9medium
Affected software
Mikrotik
RouterOS
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability (CWE-841) in Mikrotik RouterOS SSH occurs because the SSH server enters the connection protocol after a client-requested rekey even though user authentication has not been completed. This flaw allows an unauthenticated attacker to open a session channel and send exec requests, which the server dispatches. Consequently, the attacker can create, overwrite, or reconstruct files in the RouterOS managed file namespace, including critical support files that contain configuration and diagnostic data. The vulnerability affects versions prior to 6.49.21 for the 6.x branch, prior to 7.23.4 for the 7.x Long-term branch, and prior to 7.24.2 for the 7.x Stable branch. The issue has been addressed in these fixed versions.
Potential Impact
An unauthenticated attacker can exploit this vulnerability to execute commands on the RouterOS device via SSH without authentication, leading to unauthorized file creation, modification, or reconstruction within the device's managed file namespace. This could compromise device configuration and diagnostic data integrity, potentially impacting device operation and security.
Mitigation Recommendations
This vulnerability is fixed in Mikrotik RouterOS versions 6.49.21 (Long-term), 7.23.4 (Long-term), and 7.24.2 (Stable). Users should upgrade affected RouterOS installations to these or later versions to remediate the issue. No additional mitigations are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CERT-PL
- Date Reserved
- 2026-07-29T11:59:30.538Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a9c76bdacd9273b4957266d
Added to database: 09/05/2026, 20:08:29 UTC
Last enriched: 09/26/2026, 02:31:00 UTC
Last updated: 10/19/2026, 18:48:22 UTC
Views: 170
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