SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-67279
StatePUBLISHED
AssignerCERT-PL
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-05 20:17:18 UTC
Updated2026-09-05 21:16:50 UTC
DescriptionRouterOS 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)

Risk And Classification

Primary CVSS: v4.0 6.9 MEDIUM from [email protected]

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

Problem Types: CWE-841 | CWE-841 CWE-841 Improper enforcement of behavioral workflow

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary6.9MEDIUMCVSS: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/C...
4.0CNACVSS6.9MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mikrotik RouterOS affected 7.24 7.24.2 custom Not specified
CNA Mikrotik RouterOS affected 7.0.0 7.23.4 custom Not specified
CNA Mikrotik RouterOS affected 6.0.0 6.49.21 custom Not specified

References

ReferenceSourceLinkTags
cert.pl/en/posts/2026/09/mikrotik-routeros-cve [email protected] cert.pl
npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they... [email protected] npratley.net
forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 [email protected] forum.mikrotik.com
cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-activel... [email protected] cert.pl
forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 [email protected] forum.mikrotik.com
forum.mikrotik.com/t/7-24-2-stable-is-released/272800 [email protected] forum.mikrotik.com
mikrotik.com/supportsec/september-2026-vulnerability [email protected] mikrotik.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Sławomir Rozbicki (CERT.PL) (en)

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