CVE-2021-33016
No exploitation reported by the sources we read.
- Published2022-05-26
- Fixed in8.7
- WeaknessCWE-798
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
An attacker can gain full access (read/write/delete) to sensitive folders due to hard-coded credentials on KUKA KR C4 control software for versions prior to 8.7 or any product running KSS.
Timeline
dates in UTC- 2022-05-2617:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-33016?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-33016?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 8.7 | < 8.7 | 8.7 | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| — | all versions | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
KUKA KR C4
KSS: All versions · KR C4: All versions prior to 8.7
Fix
- Update Kuka kr c4 firmware to 8.7
- Mitigation from the vendor CISA ICSA-21-208-01 · 2 productsKUKA recommends users change default passwords for versions KSS 8.3 and later when possible. KSS versions 8.2 and prior are no longer supported and do not support password changes. External measures may be required to restrict network-level access and physical access to these systems. Please contac…
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- 2022-05-26
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-33016?
Is CVE-2021-33016 actively exploited?
What is the CVSS score for CVE-2021-33016?
Running KUKA KR C4? Hear about its next vulnerability
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.