Confused Deputy in Kubernetes

Answer in brief

CVE-2021-25740 records a Low severity (CVSS 3.1) vulnerability in Confused Deputy in Kubernetes. The current sources do not mark it as known exploited. The current feed maps k8s.io/kubernetes (go), k8s.io/kubernetes (go). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 21, 2021Updated Sep 10, 2026Source checked Sep 17, 2026First seen by HOL Jun 11, 2026Material review Sep 10, 2026

Upstream Advisory

Key facts

Risk: Low · CVSS 3.1
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

CVSS is 3.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps k8s.io/kubernetes (go), k8s.io/kubernetes (go). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
k8s.io/kubernetesgo	<=1.22.2	Not reported
k8s.io/kubernetesgo	>=0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for k8s.io/kubernetes, k8s.io/kubernetes.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 21, 2021
Evidence: source:osv:source_dates:source-dates:record
Source modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:record
First seen by HOL
Jun 11, 2026

Sources and claim methodology

Upstream source description

A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.

Quoted source text, attributed separately from HOL analysis.