Kubernetes man in the middle using LoadBalancer or ExternalIPs

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Summary

CVECVE-2020-8554
StatePUBLISHED
Assignerkubernetes
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-01-21 17:15:13 UTC
Updated2026-06-01 23:16:13 UTC
DescriptionKubernetes API server in all versions allow an attacker who is able to create a ClusterIP service and set the spec.externalIPs field, to intercept traffic to that IP address. Additionally, an attacker who is able to patch the status (which is considered a privileged operation and should not typically be granted to users) of a LoadBalancer service can set the status.loadBalancer.ingress.ip to similar effect.

Risk And Classification

Primary CVSS: v3.1 5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS: 0.092740000 probability, percentile 0.948200000 (date 2026-07-21)

Problem Types: CWE-283 | NVD-CWE-noinfo | CWE-283 CWE-283 Unverified Ownership

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5MEDIUMCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
3.1[email protected]Secondary6.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
3.1CNADECLARED6.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
2.0[email protected]Primary6AV:N/AC:M/Au:S/C:P/I:P/A:P

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

CVSS v2.0 Breakdown

Access Vector
Network
Access Complexity
Medium
Authentication
Single
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:M/Au:S/C:P/I:P/A:P

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Kubernetes Kubernetes All All All All
Application Oracle Communications Cloud Native Core Network Slice Selection Function 1.2.1 All All All
Application Oracle Communications Cloud Native Core Policy 1.15.0 All All All
Application Oracle Communications Cloud Native Core Service Communication Proxy 1.14.0 All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Kubernetes Kubernetes affected * semver Not specified

References

ReferenceSourceLinkTags
[Security Advisory] CVE-2020-8554: Man in the middle using LoadBalancer or ExternalIPs af854a3a-2127-422b-91ae-364da2661108 groups.google.com Mailing List, Third Party Advisory
Oracle Critical Patch Update Advisory - April 2022 af854a3a-2127-422b-91ae-364da2661108 www.oracle.com Patch, Third Party Advisory
Pony Mail! af854a3a-2127-422b-91ae-364da2661108 lists.apache.org
Oracle Critical Patch Update Advisory - July 2021 af854a3a-2127-422b-91ae-364da2661108 www.oracle.com Patch, Third Party Advisory
Oracle Critical Patch Update Advisory - January 2022 af854a3a-2127-422b-91ae-364da2661108 www.oracle.com Patch, Third Party Advisory
RESERVED · Issue #97076 · kubernetes/kubernetes · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Exploit, Third Party Advisory
Pony Mail! af854a3a-2127-422b-91ae-364da2661108 lists.apache.org
kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves [email protected] kubernetes.io
Pony Mail! af854a3a-2127-422b-91ae-364da2661108 lists.apache.org
Pony Mail! af854a3a-2127-422b-91ae-364da2661108 lists.apache.org
Pony Mail! MITRE lists.apache.org
Pony Mail! MITRE lists.apache.org
Pony Mail! MITRE lists.apache.org
Pony Mail! MITRE lists.apache.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Etienne Champetier (@champtar) of Anevia (en)

Additional Advisory Data

Workarounds

CNA: To restrict the use of external IPs we are providing an admission webhook container: k8s.gcr.io/multitenancy/externalip-webhook:v1.0.0. The source code and deployment instructions are published at https://github.com/kubernetes-sigs/externalip-webhook. Alternatively, external IPs can be restricted using OPA Gatekeeper. A sample ConstraintTemplate and Constraint can be found here: https://github.com/open-policy-agent/gatekeeper-library/tree/master/library/general/externalip.

Legacy QID Mappings

  • 900263 CBL-Mariner Linux Security Update for kubernetes-1.18.17 1.18.17
  • 900264 CBL-Mariner Linux Security Update for kubernetes 1.18.17
  • 900265 CBL-Mariner Linux Security Update for kubernetes-1.18.14 1.18.14
  • 900266 CBL-Mariner Linux Security Update for kubernetes-1.19.7 1.19.7
  • 900267 CBL-Mariner Linux Security Update for kubernetes-1.19.9 1.19.9
  • 900268 CBL-Mariner Linux Security Update for kubernetes-1.20.2 1.20.2
  • 900269 CBL-Mariner Linux Security Update for kubernetes-1.20.5 1.20.5
  • 900270 CBL-Mariner Linux Security Update for python-kubernetes 11.0.0
  • 903524 Common Base Linux Mariner (CBL-Mariner) Security Update for kubernetes (6284)
  • 905971 Common Base Linux Mariner (CBL-Mariner) Security Update for kubernetes (6284-1)
  • 907546 Common Base Linux Mariner (CBL-Mariner) Security Update for kubernetes (31731-1)

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