Is CVE-2026-40886 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-40886 being exploited in the wild.

How severe is CVE-2026-40886?

High severity, with a CVSS score of 7.7, published 23 April 2026.

Which products and versions are affected?

Argo Project Workflows >= 3.6.5, = 3.7.0, = 4.0.0, <= 4.0.4; 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) SEMVER:introduced=3.6.5, SEMVER:introduced=3.7.0,fixed=3.7.14; and 1 more.

Is there a fix for CVE-2026-40886?

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-2026-40886 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-40886?

Check whether you run Argo Project 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.

CVE-2026-40886: Argo Workflows denial of service via malformed pod annotation

Q: Is there a fix for CVE-2026-40886?

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.

Q: How is CVE-2026-40886 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-40886?

Check whether you run Argo Project 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.

CVE-2026-40886 · Severity: high · CVSS 7.7 · Published 2026-04-23

Argo Workflows is an automation engine used to run complex parallel jobs on Kubernetes clusters. A vulnerability allows any user with permission to create workflows to crash the central controller by providing a malformed configuration. This results in a persistent denial-of-service where all workflow processing across the entire cluster is halted until the malicious entry is manually removed.

Technologies: Argo Project 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-2026-40886 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-40886 being exploited in the wild.
How severe is CVE-2026-40886?: High severity, with a CVSS score of 7.7, published 23 April 2026.
Which products and versions are affected?: Argo Project Workflows >= 3.6.5, <= 3.6.19; >= 3.7.0, <= 3.7.13; >= 4.0.0, <= 4.0.4; 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) SEMVER:introduced=3.6.5, SEMVER:introduced=3.7.0,fixed=3.7.14; and 1 more.
Is there a fix for CVE-2026-40886?: 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-2026-40886 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-40886?: Check whether you run Argo Project 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 improper validation of an array index (CWE-129) exists in the Argo Workflows controller's pod informer. Specifically, the podGCFromPod() function splits the 'workflows.argoproj.io/pod-gc-strategy' annotation value by a forward slash and unconditionally attempts to access the second element of the resulting array. If a user submits a workflow with an annotation lacking a slash, the controller triggers an out-of-bounds panic. Because this panic occurs within an informer goroutine outside the main recovery scope, the entire controller process crashes. The malicious pod remains in the cluster, leading to a persistent CrashLoopBackOff state that prevents any other workflows from being processed. The issue is resolved in versions 3.7.14 and 4.0.5.

Affected products

argoproj Argo Workflows >= 3.6.5, <= 3.6.19; >= 3.7.0, <= 3.7.13; >= 4.0.0, <= 4.0.4
Red Hat Red Hat OpenShift AI (RHOAI)

Identifiers

CVE-2026-40886
GHSA-5jv8-h7qh-rf5p
GO-2026-5148

Timeline

2026-04-23: disclosed
2026-04-23: advisory
2026-04-23: patched

References

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