Denial of service in MikroTik RouterOS

Published: 2020-09-15 | Updated: 2020-09-21
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-11881
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
MikroTik RouterOS
Hardware solutions / Routers & switches, VoIP, GSM, etc

Vendor MikroTik

Security Bulletin

This security bulletin contains information about 1 vulnerabilities.

Updated 21.09.2020

Added fixed version.

1) Improper Validation of Array Index

EUVDB-ID: #VU46736

Risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-11881

CWE-ID: CWE-129 - Improper Validation of Array Index

Exploit availability: Yes


The vulnerability allows a remote attacker to perform denial of service attack.

The vulnerability exists due to improper validation of array index when processing setup-requests in a built-in SMB server. A remote non-authenticated attacker can send specially crafted setup-request packets and crash the SMB server.


Install updates from vendor's website.

Vulnerable software versions

MikroTik RouterOS: 6.41.3 - 6.47.3

External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected device in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.