CVE-2021-4178
A public proof of concept exists; no exploitation attested.
- Published2022-08-24
- Fixed in5.11.2 · 5.10.2 · 5.8.1 · 5.7.4 · 5.3.2 · 5.1.2
- WeaknessCWE-502
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
A arbitrary code execution flaw was found in the Fabric 8 Kubernetes client affecting versions 5.0.0-beta-1 and above. Due to an improperly configured YAML parsing, this will allow a local and privileged attacker to supply malicious YAML.
Timeline
dates in UTC- 2022-08-2416:15CVE publishedNVD
- 2026-10-2319:23First public proof of conceptPoC-in-GitHub
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-4178?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-4178?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD · OSV| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 5.11 | ≥ 5.11.0, < 5.11.2 | 5.11.2 | NVD · OSV |
| 5.x | ≥ 5.9.0, < 5.10.2 | 5.10.2 | NVD · OSV |
| 5.8 | ≥ 5.8.0, < 5.8.1 | 5.8.1 | OSV |
| 5.x | ≥ 5.5.0, < 5.7.4 | 5.7.4 | NVD · OSV |
| 5.x | ≥ 5.2.0, < 5.3.2 | 5.3.2 | NVD · OSV |
| 5.1 | ≥ 5.1.0, < 5.1.2 | 5.1.2 | NVD · OSV |
| 5.0 | ≥ 5.0.1, < 5.0.3 | 5.0.3 | NVD |
| 5.0 | ≥ 5.0.0-beta-1, < 5.0.3 | 5.0.3 | OSV |
| 5.0 | = 5.0.0 | no fix published | NVD |
| 5.8 | = 5.8.0 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 2.0 | = 2.0.1 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 2.2 | = 2.2.5 | no fix published | NVD |
6 more products in the sources.
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Redhat fabric8-kubernetes to 5.11.2 · 5.10.2 · 5.8.1 · 5.7.4 · 5.3.2 · 5.1.2 · 5.0.3
Advisories and patches
- access.redhat.comVendor Advisory
- bugzilla.redhat.comVendor Advisory
Detection
read 2026-10-23 19:23 UTC- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- 1 repository, unverifiedshoucheng3/fabric8io__kubernetes-client_CVE-2021-4178_5-0-2 PoC-in-GitHub
Sources
- NVDCVSS 3.16.7read 2026-10-23
- CNAweakness (CWE)CWE-502read 2026-10-23
- NVDweakness (CWE)CWE-502read 2026-10-23
- FIRST EPSSEPSS score0.3 %2026-10-23
- PoC-in-GitHubproof of concept1read 2026-10-23
- OSVaffected packages—
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- Published
- 2022-08-24
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-4178?
Is CVE-2021-4178 actively exploited?
What is the CVSS score for CVE-2021-4178?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.