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Successful exploitation of this vulnerability could allow an attacker to achieve remote code execution or cause a denial of service.
The following versions of MikroTik RouterOS are affected:
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The web management service in affected RouterOS versions contains an integer underflow in its HTTP request body handling that is reachable before authentication. This can be leveraged by an unauthenticated network attacker to achieve arbitrary code execution as root, or to cause a denial of service, using a single crafted request.
View CVE Details
MikroTik
Product Version:
MikroTik RouterOS: <7.24
Product Status:
known_affected
Vendor fix
MikroTik recommends users update RouterOS to version 7.23 or later. The upgrade can be downloaded from the MikroTik website.
https://mikrotik.com/download
Relevant CWE: CWE-191 Integer Underflow (Wrap or Wraparound)
This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.
Summary
Successful exploitation of this vulnerability could allow an attacker to achieve remote code execution or cause a denial of service.
The following versions of MikroTik RouterOS are affected:
- RouterOS <7.24 (CVE-2026-84411)
| CVSS | Vendor | Equipment | Vulnerabilities |
|---|---|---|---|
| v3 9.8 | MikroTik | MikroTik RouterOS | Integer Underflow (Wrap or Wraparound) |
Background
- Critical Infrastructure Sectors: Communications, Information Technology
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: Latvia
Vulnerabilities
Expand All +
CVE-2026-84411
The web management service in affected RouterOS versions contains an integer underflow in its HTTP request body handling that is reachable before authentication. This can be leveraged by an unauthenticated network attacker to achieve arbitrary code execution as root, or to cause a denial of service, using a single crafted request.
View CVE Details
Affected Products
MikroTik RouterOS
Vendor:MikroTik
Product Version:
MikroTik RouterOS: <7.24
Product Status:
known_affected
Remediations
Vendor fix
MikroTik recommends users update RouterOS to version 7.23 or later. The upgrade can be downloaded from the MikroTik website.
https://mikrotik.com/download
Relevant CWE: CWE-191 Integer Underflow (Wrap or Wraparound)
Metrics
| CVSS Version | Base Score | Base Severity | Vector String |
|---|---|---|---|
| 3.1 | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 4.0 | 9.3 | CRITICAL | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
Acknowledgments
- An anonymous researcher reported this vulnerability to CISA.
Legal Notice and Terms of Use
This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
Recommended Practices
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability.
- Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
- Locate control system networks and remote devices behind firewalls and isolating them from business networks.
- When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time.
Revision History
- Initial Release Date: 2026-09-29
| Date | Revision | Summary |
|---|---|---|
| 2026-09-29 | 1 | Initial Publication |