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.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-g3xr-5w5j-w4q4 Contour has Improper JWT Verification for Non-SNI Requests on Virtual Hosts with Fallback Certificate Enabled
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 25 Aug 2026 02:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 19 Aug 2026 14:30:00 +0000

Type Values Removed Values Added
Description A flaw was found in Contour. When an HTTPProxy is configured with both a fallback certificate and JWT (JSON Web Token) providers, Contour does not properly enforce JWT verification. This allows remote attackers to bypass security checks by sending requests without a valid token, specifically when clients do not provide a TLS Server Name Indication (SNI) or provide an unrecognized SNI. The consequence is unauthorized access to upstream services and potential information disclosure. 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.
Title contour: Contour: JWT verification bypass allows unauthorized access via HTTPProxy misconfiguration Contour has Improper JWT Verification for Non-SNI Requests on Virtual Hosts with Fallback Certificate Enabled

Wed, 15 Jul 2026 14:30:00 +0000

Type Values Removed Values Added
First Time appeared Projectcontour
Projectcontour contour
Vendors & Products Projectcontour
Projectcontour contour

Wed, 15 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in Contour. When an HTTPProxy is configured with both a fallback certificate and JWT (JSON Web Token) providers, Contour does not properly enforce JWT verification. This allows remote attackers to bypass security checks by sending requests without a valid token, specifically when clients do not provide a TLS Server Name Indication (SNI) or provide an unrecognized SNI. The consequence is unauthorized access to upstream services and potential information disclosure.
Title contour: Contour: JWT verification bypass allows unauthorized access via HTTPProxy misconfiguration
Weaknesses CWE-295
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N'}

threat_severity

Moderate


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-25T02:03:11.629Z

Reserved: 2026-06-03T20:54:20.431Z

Link: CVE-2026-50149

cve-icon Vulnrichment

Updated: 2026-08-25T02:03:07.731Z

cve-icon NVD

Status : Received

Published: 2026-08-19T15:17:08.710

Modified: 2026-08-25T03:16:55.457

Link: CVE-2026-50149

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-02T17:15:20Z

Links: CVE-2026-50149 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-20T16:30:04Z

Weaknesses