CVE-2020-20021Public exploitNetwork attack vector

Unauthenticated service interruption

Published Jul 12, 2023 · Updated Jul 9, 2026

Denial of service in MikroTik RouterOS 6.46.3 and earlier allows remote attackers to interrupt routers through the SSH service. The CNA describes only an SSH daemon misconfiguration and publishes no configuration setting or request-handling operation that causes the failure. Network access to SSH is the reported gate; the record does not establish whether the service hangs, crashes, or forces a router reboot.

CVSS severity7.5
High
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in MikroTik RouterOS 6.46.3 and earlier allows remote attackers to interrupt routers through the SSH service. The CNA describes only an SSH daemon misconfiguration and publishes no configuration setting or request-handling operation that causes the failure. Network access to SSH is the reported gate; the record does not establish whether the service hangs, crashes, or forces a router reboot.

The record

CVE
CVE-2020-20021
Published
Jul 12, 2023
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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