CyberSecBulletin
CVE-2026-86060Exploited in the wildNVD status: Analyzed

MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command

Published Updated By the CyberSecBulletin desk

CVE-2026-86060 is a critical-severity improper neutralization of argument delimiters in a command vulnerability in RouterOS from MikroTik, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 7.24.2, 7.23.4, 6.49.21 as the first without the flaw, so updating RouterOS to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on September 10, 2026, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update RouterOS to 7.24.2 or 7.23.4 or 6.49.21, whichever matches your release line, or a later version.
  2. CISA's 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.
  3. Read the advisory on mikrotik.com for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
MikrotikRouterOS7.24 up to, but not including, 7.24.2; 7.0.0 up to, but not including, 7.23.4; 6.0.0 up to, but not including, 6.49.217.24.2, 7.23.4, 6.49.21

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.09.2CriticalCNA (cert.pl)
CVSS 3.19.8CriticalNVD

Official description

RouterOS contains an argument-handling flaw in the SSH login path involving usernames that begin with a prohibited character, allowing for the trusted RouterOS policy mask to be changed, leading to privilege escalation. Exploitation requires an unauthenticated SSH session to reach the RouterOS login helper.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Neutralization of Argument Delimiters in a Command

The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.

How developers prevent this class of flaw

  • Understand all the potential areas where untrusted inputs can enter your product: parameters or arguments, cookies, anything read from the network, environment variables, request headers as well as content, URL components, e-mail, files, databases, and any external systems that provide data to the application. Perform input validation at well-defined interfaces.
  • Directly convert your input type into the expected data type, such as using a conversion function that translates a string into a number. After converting to the expected data type, ensure that the input's values fall within the expected range of allowable values and that multi-field consistencies are maintained.
  • When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.

More Improper Neutralization of Argument Delimiters in a Command vulnerabilities (CWE-88)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
  3. Added to CISA's Known Exploited Vulnerabilities catalogue.
  4. Record last changed materially (score, affected products, status or references).
  5. Deadline for US federal agencies to remediate, set by CISA.

References

Technical write-ups (may include proof of concept)

Our coverage

Other vulnerabilities in RouterOS

All RouterOS vulnerabilities

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