Contour has Improper JWT Verification for Non-SNI Requests on Virtual Hosts with Fallback Certificate Enabled (CVE-2026-50149) | HOL Guard CVE

Medium · CVSS 6.5CVE-2026-50149GHSA-G3XR-5W5J-W4Q4

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

Answer in brief

CVE-2026-50149 records a Medium severity (CVSS 6.5) vulnerability in Contour has Improper JWT Verification for Non-SNI Requests on Virtual Hosts with Fallback Certificate Enabled. The current sources do not mark it as known exploited. The current feed maps projectcontour/contour (generic), github.com/projectcontour/contour (go), github.com/projectcontour/contour (go). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 19, 2026Updated Aug 25, 2026Source checked Sep 17, 2026First seen by HOL Jul 2, 2026Material review Aug 25, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.5
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps projectcontour/contour (generic), github.com/projectcontour/contour (go), github.com/projectcontour/contour (go). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
projectcontour/contourgeneric	>= 1.23.0, < 1.33.5	Not reported
github.com/projectcontour/contourgo	>=1.23.0,<1.33.5	1.33.5
github.com/projectcontour/contourgo	>=1.23.0 <1.33.5	1.33.5

Recommended response

Check inventory. Check lockfiles and deployed manifests for projectcontour/contour, github.com/projectcontour/contour, github.com/projectcontour/contour.
Review the reported fix. Update github.com/projectcontour/contour to 1.33.5; github.com/projectcontour/contour to 1.33.5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jul 2, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.