CVE-2026-28229

CriticalPublic PoC

Published: 11 March 2026

Published

11 March 2026

Modified

20 March 2026

KEV Added

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Patch

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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0006 19.4th percentile

Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-28229 is a critical-severity Incorrect Authorization (CWE-863) vulnerability in Argoproj Argo Workflows. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 19.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 AC-14 (Permitted Actions Without Identification or Authentication) and AC-3 (Access Enforcement).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

AC-3 Access Enforcement good match

prevent

AC-3 mandates enforcement of approved authorizations for access to system resources, directly preventing unauthorized retrieval of sensitive WorkflowTemplates via API endpoints.

AC-14 Permitted Actions Without Identification or Authentication good match

prevent

AC-14 explicitly identifies and authorizes only permitted actions without identification or authentication, mitigating bypasses using trivial tokens like 'Bearer nothing'.

SI-2 Flaw Remediation good match

prevent

SI-2 requires timely identification, reporting, and correction of flaws, enabling patching to remediated Argo Workflows versions 4.0.2 or 3.7.11.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1552.001 Credentials In Files Credential Access

Adversaries may search local file systems and remote file shares for files containing insecurely stored credentials.

attack.mitre.org →

Why these techniques?

CVE enables unauthenticated exploitation of exposed Argo Workflows API endpoints (T1190) resulting in direct retrieval of WorkflowTemplates containing embedded Kubernetes Secrets and credentials (T1552.001).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. Prior to 4.0.2 and 3.7.11, Workflow templates endpoints allow any client to retrieve WorkflowTemplates (and ClusterWorkflowTemplates). Any request with a Authorization: Bearer nothing token can…

leak sensitive template content, including embedded Secret manifests. This vulnerability is fixed in 4.0.2 and 3.7.11.

Deeper analysisAI

CVE-2026-28229 is a critical authorization bypass vulnerability (CWE-863) in Argo Workflows, an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. Versions prior to 4.0.2 and 3.7.11 expose WorkflowTemplates and ClusterWorkflowTemplates endpoints that permit unauthorized access to sensitive template content. Specifically, any client can retrieve these resources by sending a request with an "Authorization: Bearer nothing" token, leading to the leakage of embedded Secret manifests and other confidential data. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attackers require only network access to the affected Argo Workflows API server, with no privileges, authentication, or user interaction needed. A remote unauthenticated adversary can exploit this by crafting a simple HTTP GET request to the templates endpoints using the trivial "Bearer nothing" token, immediately obtaining sensitive WorkflowTemplate contents. This disclosure enables attackers to extract embedded Kubernetes Secrets, potentially exposing credentials, API keys, or other high-value data stored within workflows, which could facilitate further compromise of the Kubernetes cluster or orchestrated workloads.

The Argo Workflows security advisory (GHSA-56px-hm34-xqj5) confirms the issue and states that it is fully remediated in versions 4.0.2 and 3.7.11. Security practitioners should upgrade to these patched releases immediately, verify endpoint access controls, and audit existing WorkflowTemplates for embedded Secrets as a defensive measure.