CVE-2026-50149

MediumCVSS 6.5

Published: 19/08/2026(UTC)Translated: 19/08/2026(UTC)NVD NIST

Summary

Contour versions 1.23.0 through 1.33.4 contain a vulnerability where when an HTTPProxy is configured with an incompatible combination of .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 bypass configured JWT verification and are proxied to upstream services without a valid token. This issue is fixed in Contour v1.33.5, which rejects and marks invalid such HTTPProxy resources.

Risk Assessment

An attacker can bypass JWT verification and gain access to services without a valid token, potentially leading to unauthorized access to protected resources.

Recommendation

Update Contour to version 1.33.5 or later, which includes fixes for the vulnerability. As a workaround, do not enable enableFallbackCertificate on HTTPProxy resources that also define jwtProviders.

Original NVD description (English source)

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.