SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS
Affects MikroTik RouterOS 6.0.0 before 6.49.21, 7.0.0 before 7.23.4, and 7.24 before 7.24.2, where the SSH port is reachable over the network. Fixed in the listed releases.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Actively exploited
- Fix
- Fixed in 7.24.2, 7.23.4, 6.49.21
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: active
- Automatable: yes
- Technical impact: partial
Summary
MikroTik RouterOS, the network operating system on MikroTik routers, is affected. An unauthenticated attacker can exploit its SSH service to create, overwrite, or reconstruct files on the device, including support files that contain configuration and diagnostic data.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original 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)
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: active · Automatable: yes · Technical impact: partial
- Added to CISA KEV
CISA has evidence of exploitation in the wild
- Record last updated
- CISA remediation deadline
Due date for US federal agencies to patch
Affected versions
- Mikrotik RouterOS
From 7.24 · fixed in 7.24.2; From 7.0.0 · fixed in 7.23.4; From 6.0.0 · fixed in 6.49.21
References 7
cert.pl
mikrotik.com
Questions about CVE-2026-67279
What does this mean?
An attacker who can reach the router's SSH port can run commands on the router without logging in. The flaw is a state bypass in SSH rekeying that happens before authentication.Source: mikrotik.com
Am I affected, and how do I check?
RouterOS 6.0.0 before 6.49.21, 7.0.0 before 7.23.4, and 7.24 before 7.24.2 are affected. To check the installed version, run /system resource print on the router and read the version field.Source: mikrotik.com
What should I do about it?
Upgrade to 6.49.21, 7.23.4, or 7.24.2, whichever matches the router's release branch. Until the upgrade is done, make sure SSH is not open to any untrusted networks.Source: mikrotik.com
Is it being exploited?
Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-09-25, which means it has evidence of attacks. No public exploit code is tracked.Source: cisa.gov, cve.now feed data