CVE-2026-40886
Argo Workflows: Unchecked annotation parsing in pod informer crashes Argo Workflows controller
Description
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.
How to fix CVE-2026-40886
To remediate CVE-2026-40886, upgrade the affected package to a fixed version below.
- —upgrade to 3.7.14 or later
- —upgrade to 3.7.14 or later
- —upgrade to 4.0.5 or later
Is CVE-2026-40886 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- >= 3.6.5, < 3.7.14, >= 4.0.0, < 4.0.5
- >= 3.7.0, < 3.7.14
- >= 4.0.0, < 4.0.5
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H |