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Full vulnerability report · 2022
CVE-2020-8562High confidence

Bypass of Kubernetes API Server proxy TOCTOU

Kubernetes · Kubernetes

2.2LowCVSS 3.1
Recommended action
Scheduled

Low technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Mitigation available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2020-8562 · CSAF 2.0 · revision 3 · status not statedRed Hat Product Securitykubernetes: Bypass of Kubernetes API Server proxy TOCTOU
22 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • atomic-openshift as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-clients as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-clients-redistributable as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-docker-excluder as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-excluder as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-hyperkube as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-hypershift as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-master as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-node as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-pod as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-sdn-ovs as a component of Red Hat OpenShift Container Platform 3.11
  • atomic-openshift-template-service-broker as a component of Red Hat OpenShift Container Platform 3.11
Summary
A security issue was discovered in Kubernetes where an authorized user may be able to access private networks on the Kubernetes control plane components. Kubernetes clusters are only affected if an untrusted user can create or modify Node objects and proxy to them, or an untrusted user can create or modify StorageClass objects and access KubeControllerManager logs.
Remediation
Fix deferred
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2022-1153

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Low technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Mitigation available
01

What, why and how

As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.

What

As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.

Why

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.

Why

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Time-of-check Time-of-use (TOCTOU) Race Condition → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
High: elevated access is required
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-367 ↗

CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkCWE-367
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2024-1488IBM InfoSphere Information Server: Mehrere Schwachstellen

Ein entfernter Angreifer kann mehrere Schwachstellen in IBM InfoSphere Information Server ausnutzen, um beliebigen Programmcode auszuführen, einen Cross-Site-Scripting-Angriff durchzuführen, Sicherheitsmaßnahmen zu umgehen, einen Denial-of-Service-Zustand zu erzeugen und vertrauliche Informationen offenzulegen.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Mitigation available
Affected
atomic-openshift as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-clients as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-clients-redistributable as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-docker-excluder as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-excluder as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-hyperkube as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-hypershift as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-master as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-node as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-pod as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-sdn-ovs as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-template-service-broker as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift-tests as a component of Red Hat OpenShift Container Platform 3.11; atomic-openshift.src as a component of Red Hat OpenShift Container Platform 3.11; openshift-clients as a component of Red Hat OpenShift Container Platform 4; openshift-clients-redistributable as a component of Red Hat OpenShift Container Platform 4; openshift-hyperkube as a component of Red Hat OpenShift Container Platform 4; openshift-kube-apiserver as a component of Red Hat OpenShift Container Platform 4; openshift-kube-controller-manager as a component of Red Hat OpenShift Container Platform 4; openshift-kube-scheduler as a component of Red Hat OpenShift Container Platform 4; openshift-kubelet as a component of Red Hat OpenShift Container Platform 4; openshift.src as a component of Red Hat OpenShift Container Platform 4
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Apply the mitigation in the linked authoritative guidance while planning the vendor's permanent fix.
Workaround
A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
04

Evidence and provenance

Published 1 Feb 2022 · Last source change 1 Jun 2026, 21:45 UTC · CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2022-1153
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Mitigation reference recorded
ENISA EUVD · EUVD-2022-1153↗Vendor CSAF · Red Hat Product Security↗Mitigation reference↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2020-8562 · cve.blacktree.nl