Argo Workflows: SSO RBAC Delegation Nil Pointer Dereference DoS (gatekeeper.go)

{
  "id": "bcd49191500de47f7ced73d3f255342e2c07f1d08f5ccc85bd593938f6daaf99",
  "url": "https://osv.dev/vulnerability/CVE-2026-42183",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Argo Workflows: SSO RBAC Delegation Nil Pointer Dereference DoS (gatekeeper.go)",
    "summary": "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.",
    "evidence": "osv:CVE-2026-42183",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2026-42183",
      "aliases": [
        "BIT-argo-workflows-2026-42183",
        "CVE-2026-42183",
        "GHSA-p4gq-3vxj-f4jq",
        "GO-2026-5527"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/argoproj/argo-workflows",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a8bff4a72130bc1a13d95c6f73ff3fafec880287"
                },
                {
                  "fixed": "0ab1452144d8f4d57c50b37ce50dad218868e950"
                },
                {
                  "fixed": "c4cc17d0c034fa9a9cc01ef1af6c8016c93071d4"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:argoproj:argo_workflows:*:*:*:*:*:go:*:*",
                    "range": [
                      {
                        "introduced": "4.0.0"
                      },
                      {
                        "fixed": "4.0.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c4cc17d0c034fa9a9cc01ef1af6c8016c93071d4"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "0ab1452144d8f4d57c50b37ce50dad218868e950"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v4.0.5"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v4.0.4",
            "v4.0.3",
            "v4.0.2",
            "v4.0.1",
            "v4.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42183.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:45.816647953Z",
      "provider": "osv",
      "references": [
        "https://github.com/argoproj/argo-workflows/releases/tag/v4.0.5",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42183.json",
        "https://github.com/argoproj/argo-workflows/security/advisories/GHSA-p4gq-3vxj-f4jq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-42183",
        "https://github.com/argoproj/argo-workflows/commit/c4cc17d0c034fa9a9cc01ef1af6c8016c93071d4"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-476"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42183.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-42183",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 513607,
  "published_at": "2026-05-09T03:44:10.712+00:00"
}