CVE-2026-67279: MikroTik RouterOS SSH runs commands before login (exploited)

Exploited in the wild Medium 6.9 EPSS 2.3% MikroTik RouterOS

The RouterOS SSH server moves to the connection phase after a client-requested rekey even though no login took place, so an unauthenticated client can open a session and send an exec request. Chained with CVE-2026-86060 it gives an attacker full control of a router whose SSH service is reachable; attackers used the chain from at least 2 September 2026 to create a privileged user named 'ops'. CISA added it to the Known Exploited Vulnerabilities catalog on 25 September 2026. Fixed in RouterOS 6.49.21, 7.23.4 and 7.24.2; install the current release of your channel.

Also known as “MikroTrick”.

CVE-2026-67279CVE identifier
6.9CVSS 4.0 base score (medium)
2026-09-25added to CISA's exploited list (US federal deadline 2026-09-28)
2.3%EPSS: chance of exploitation in the next 30 days (higher than 83% of CVEs)
2026-09-05published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

What to do now

Check whether you run MikroTik RouterOS and which version (commands below).
Install the fixed version for your system: see “Patch it” below.
Installing a RouterOS update always reboots the router. On RouterBOARD hardware, run /system routerboard upgrade afterwards and reboot a second time so the matching RouterBOOT firmware is loaded. Plan for two short outages and make sure you have out-of-band or local access in case the router does not come back.
If you cannot patch today, apply the temporary mitigation below and patch as soon as possible.
Because this flaw is being exploited, also check the server for signs of compromise.

Affected and fixed versions

Affected:

RouterOS 6.0 before 6.49.21
RouterOS 7.0 before 7.23.4
RouterOS 7.24 before 7.24.2

Fixed in:

RouterOS 6.49.21 (RouterOS 6)
RouterOS 7.23.4 (long-term at the time)
RouterOS 7.24.2 (stable at the time)
Recommended as of 3 Nov 2026: 7.25 (stable), 7.24.6 (long-term) or 6.49.23

Am I affected?

/system resource print   # version, architecture-name, board-name
/system package update print   # channel, installed-version, latest-version
/system routerboard print   # current-firmware vs upgrade-firmware (not on CHR/x86)
/ip service print   # which management services are enabled, and from where
/ip service print where name=ssh   # exposed if enabled and available-from/address is empty

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

Built from source

# RouterOS CLI (works on v6 and v7; v7 also accepts /system/package/update/...)
# Current releases as of 3 Nov 2026: 7.25 (stable), 7.24.6 (long-term), 6.49.23 (RouterOS 6)
/system backup save name=pre-update
/export file=pre-update
/system package update set channel=long-term   # or stable
/system package update check-for-updates
/system package update print   # status should say: New version is available
/system package update install   # downloads, installs and REBOOTS the router
# after it is back up:
/system resource print   # confirm the new version
/system routerboard upgrade   # RouterBOARD only: new RouterBOOT firmware
/system reboot   # REBOOTS again to load the firmware

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

If you cannot patch yet

Updating is the fix. Until you can update: disable SSH if you do not use it: /ip service disable ssh
Or allow SSH only from management addresses. RouterOS 7.24 and later: /ip service set ssh available-from=192.0.2.0/24 (older releases call the property address=). The port still answers, so also drop it in the firewall input chain.
Firewall input chain with an address list (put the rule before any rule that accepts the traffic): /ip firewall address-list add list=mgmt address=192.0.2.0/24 then /ip firewall filter add chain=input protocol=tcp dst-port=22,8291 src-address-list=!mgmt action=drop comment="mgmt only" place-before=0. Use Safe Mode (Ctrl+X in the CLI) so a mistake is rolled back if you lose the session.
Prefer a VPN such as WireGuard for remote management instead of exposing management ports (MikroTik, CERT Polska).

Look for signs of exploitation

CERT Polska indicator log line: 'login failure for user -2 from <ip> via ssh' followed by 'user <name> added by ssh:-2@<ip>'. Search with: /log print where message~"ssh:-2" (the memory log is lost on reboot unless you log to disk or a remote syslog server).
A highly privileged user named 'ops' that nobody created (/user print). CERT Polska saw it created from 82.192.72.4 since at least 2 September 2026; 103.102.31.18 was seen attempting exploitation.
The fixed releases analyse the configuration at boot and set the device to Flagged when they find known traces of unauthorised changes: /system device-mode print shows flagged: yes and a critical log entry is written. Absence of the flag does not prove the device is clean.
After updating, MikroTik and CERT Polska advise checking for unknown users, scripts, scheduler entries, proxy settings and tunnels: /user print, /user ssh-keys print, /system script print, /system scheduler print, /ip proxy print, /ip socks print, /interface print, /ip dns print, /ip dns static print, /ip firewall nat print, /file print.
If compromise is suspected (CERT Polska): isolate the device, secure logs and configuration before any reset, report to your CSIRT, reset to factory settings and rebuild from a trusted configuration (do not restore a full backup from the possibly compromised router), and change every password, key and secret. Do not clear the Flagged state until analysis is finished.

CISA 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

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Sources

Page generated automatically from official sources on 2026-11-03 18:05 UTC and reviewed by an editor. Always confirm with your vendor's advisory.