CVE-2026-42296: Argo Workflows authorization bypass in templateReferencing Strict mode

CVE-2026-42296 · Severity: high · CVSS 8.1 · Published 2026-05-09

Argo Workflows is an automation engine used to run parallel jobs on Kubernetes clusters. A security flaw allows users with basic workflow creation permissions to bypass 'Strict' security restrictions, potentially gaining unauthorized access to the underlying host network or sensitive service accounts. This could lead to data exposure or the ability to run unauthorized tasks with elevated privileges, depending on the cluster's overall security configuration.

Technologies: Argo Project Argo Workflows, github.com/argoproj/argo-workflows (Go), github.com/argoproj/argo-workflows/v2 (Go), github.com/argoproj/argo-workflows/v3 (Go), github.com/argoproj/argo-workflows/v4 (Go). Vendors: Argo Project, Go.

Quick answers

Is CVE-2026-42296 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-42296 being exploited in the wild.
How severe is CVE-2026-42296?
High severity, with a CVSS score of 8.1, published 9 May 2026.
Which products and versions are affected?
Argo Project Argo Workflows < 3.7.14, < 3.7.14, >= 4.0.0, < 4.0.5; github.com/argoproj/argo-workflows (Go) SEMVER:introduced=0; github.com/argoproj/argo-workflows/v2 (Go) SEMVER:introduced=0; github.com/argoproj/argo-workflows/v3 (Go) < 3.7.14, SEMVER:introduced=0,fixed=3.7.14; and 1 more.
Is there a fix for CVE-2026-42296?
Yes. github.com/argoproj/argo-workflows/v3 (Go): upgrade to 3.7.14 or later; github.com/argoproj/argo-workflows/v4 (Go): upgrade to 4.0.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-42296 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-42296?
Check whether you run Argo Project Argo Workflows, github.com/argoproj/argo-workflows (Go), github.com/argoproj/argo-workflows/v2 (Go) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/argoproj/argo-workflows/v3 (Go): upgrade to 3.7.14 or later
    go get github.com/argoproj/argo-workflows/v3@v3.7.14
  • github.com/argoproj/argo-workflows/v4 (Go): upgrade to 4.0.5 or later
    go get github.com/argoproj/argo-workflows/v4@v4.0.5

Technical details

An authorization bypass exists in Argo Workflows due to an incomplete fix for a previous vulnerability. While the system correctly blocks 'podSpecPatch' when 'templateReferencing: Strict' is enabled, it fails to validate other 'WorkflowSpec' fields that are merged during pod creation. An attacker with 'create Workflow' permissions can inject fields such as 'hostNetwork', 'serviceAccountName', 'securityContext', or 'tolerations' into a workflow that references a hardened template. Because the 'JoinWorkflowSpec' logic gives priority to user-defined fields when the template relies on defaults, these overrides are applied to the resulting Kubernetes pods. This allows for privilege escalation, such as scheduling pods on control-plane nodes or mounting service account tokens. The issue is patched in versions 3.7.14 and 4.0.5.

Affected products

  • argoproj Argo Workflows < 3.7.14, >= 4.0.0, < 4.0.5

Identifiers

  • CVE-2026-42296
  • GHSA-3775-99mw-8rp4
  • GO-2026-5072

Timeline

  • 2026-04-23: advisory: GitHub Security Advisory published
  • 2026-04-23: patched: Versions 3.7.14 and 4.0.5 released
  • 2026-05-09: disclosed: CVE-2026-42296 published to NVD

References

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