CVE-2020-20741Network attack vector

Unauthenticated remote display access via retained connections

Published Jul 23, 2021 · Updated Aug 4, 2024

Authentication bypass in Beckhoff CX9020 image 6.02 build 4016.6 allows remote attackers to access CE Remote Display without valid credentials. The Windows CE endpoint keeps an incoming session open after rejecting incorrect credentials, letting a modified client continue the session. Exposure requires CE Remote Display to be enabled in a custom, older, or manually changed image; successful bypass grants unauthenticated remote-display access.

CVSS severity9.8
Critical
EPSS probability1.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Beckhoff CX9020 image 6.02 build 4016.6 allows remote attackers to access CE Remote Display without valid credentials. The Windows CE endpoint keeps an incoming session open after rejecting incorrect credentials, letting a modified client continue the session. Exposure requires CE Remote Display to be enabled in a custom, older, or manually changed image; successful bypass grants unauthenticated remote-display access.

The record

CVE
CVE-2020-20741
Published
Jul 23, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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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 NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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