Contour has Improper JWT Verification for Non-SNI Requests on Virtual Hosts with Fallback Certificate Enabled

{
  "id": "fa2b22dc88c7f3777cab549ea09a663d6dbf491e5445c4b49afcce1d32428427",
  "url": "https://osv.dev/vulnerability/CVE-2026-50149",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Contour has Improper JWT Verification for Non-SNI Requests on Virtual Hosts with Fallback Certificate Enabled",
    "summary": "Contour is a Kubernetes ingress controller using Envoy proxy. In versions 1.23.0 through 1.33.4, when an `HTTPProxy` is configured with incompatible combination of both `.spec.virtualhost.tls.enableFallbackCertificate: true` and `.spec.virtualhost.jwtProviders`, Contour does not reject the configuration. Consequently, requests from clients that do not send TLS SNI or send an unrecognized SNI (one that does not match any `HTTPProxy` FQDN) bypass configured JWT verification and are proxied to upstream services without a valid token. This issue is fixed in Contour v1.33.5. Contour now rejects and marks invalid any `HTTPProxy` resources that combine `.spec.virtualhost.tls.enableFallbackCertificate: true` with `.spec.virtualhost.jwtProviders`. Affected resources will receive a status condition with the error reason `TLSIncompatibleFeatures`. As a workaround, do not enable `.spec.virtualhost.tls.enableFallbackCertificate` on `HTTPProxy` resources that also define `.spec.virtualhost.jwtProviders`. Remove one of the two settings to avoid the invalid configuration.",
    "evidence": "osv:CVE-2026-50149",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-50149",
      "aliases": [
        "BIT-contour-2026-50149",
        "CVE-2026-50149",
        "GHSA-g3xr-5w5j-w4q4",
        "GO-2026-5889"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/projectcontour/contour",
              "type": "GIT",
              "events": [
                {
                  "introduced": "4520248139257c38e0e12498c2aedbf811b69950"
                },
                {
                  "fixed": "2713ad0e0ebd5d192a53803cef4c1c3a69692b1c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.23.0"
                      },
                      {
                        "fixed": "1.33.5"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "1.23.0"
                      },
                      {
                        "last_affected": "1.33.4"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-50149.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.496949450Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/50xxx/CVE-2026-50149.json",
        "https://github.com/projectcontour/contour/security/advisories/GHSA-g3xr-5w5j-w4q4",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-50149"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-295"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/50xxx/CVE-2026-50149.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-50149",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 488687,
  "published_at": "2026-08-19T14:16:21.476+00:00"
}