CVE-2021-33016Network attack vector

Unauthenticated sensitive-folder access via hard-coded credentials

Published May 26, 2022 · Updated Apr 16, 2025

Use of hard-coded credentials in KUKA KR C4 before 8.7 and KSS all versions allows remote attackers to access sensitive folders. The advisory identifies embedded credentials as the authentication failure but does not name the account, service, or folder paths that accept them. Network reachability is sufficient without authentication; documented impact includes reading, writing, and deleting sensitive files, which can enable unauthorized control-system access.

CVSS severity9.8
Critical
EPSS probability0.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use of hard-coded credentials in KUKA KR C4 before 8.7 and KSS all versions allows remote attackers to access sensitive folders. The advisory identifies embedded credentials as the authentication failure but does not name the account, service, or folder paths that accept them. Network reachability is sufficient without authentication; documented impact includes reading, writing, and deleting sensitive files, which can enable unauthorized control-system access.

The record

CVE
CVE-2021-33016
Published
May 26, 2022
Updated
Apr 16, 2025
Vendor
KUKA
Product
KR C4
Classifications
CWE-798, T1078.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=All <v8.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

KUKA · KR C4version=All <v8.7
KUKA · KUKA.SystemSoftwareversion=All

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
9.8ICS-CERTCVSS: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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
T1078.001Default Accounts

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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