What is CVE-2026-40886?

CVE-2026-40886 is a high-severity vulnerability in Argoproj Argo-Workflows, classified under Improper Validation of Array Index. CVSS score: 7.7/10. Published 2026-04-23.

How severe is CVE-2026-40886?

High severity. CVSS v3 base score is 7.7 out of 10.

Vulnerability in Argoproj Argo-Workflows

CVE-2026-40886

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.

Published 2026-04-23 · last modified 2026-07-15.

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.006 (47.2th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002

Affected products

Argoproj Argo-Workflows — versions >= 4.0.0, < 4.0.5, >= 3.7.0, < 3.7.14, >= 3.6.5, <= 3.6.19
Argoproj Argo Workflows

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-40886?: CVE-2026-40886 is a high-severity vulnerability in Argoproj Argo-Workflows, classified under Improper Validation of Array Index. CVSS score: 7.7/10. Published 2026-04-23.
How severe is CVE-2026-40886?: High severity. CVSS v3 base score is 7.7 out of 10.