NULL pointer dereference in Argoproj Argo-Workflows

CVE-2026-42183

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. From version 4.0.0 to before version 4.0.5, a nil pointer dereference in server/auth/gatekeeper.go rbacAuthorization() causes a panic (denial of service) for SSO users whose claims match a namespace-level RBAC rule but not an SSO-namespace rule, when SSO_DELEGATE_RBAC_TO_NAMESPACE=true. This issue has been patched in version 4.0.5.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.006 (46.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-42183: held from 0.004 to 0.006.

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

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42183?
CVE-2026-42183 is a medium-severity vulnerability in Argoproj Argo-Workflows, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2026-05-09.
How severe is CVE-2026-42183?
Medium severity. CVSS v3 base score is 6.5 out of 10.