CVE-2026-50149

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

Published: Aug 19, 2026Updated: Sep 18, 2026 Sources: CVE List NVDCWE-295

6.5MEDIUM

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:HAttack Complexity

High

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:HConfidentiality

High

I:LIntegrity

Low

A:NAvailability

None

Open in CVSS calculator →

Weaknesses

CWE-295

Affected Products

projectcontour

oss-projectaka contour

contourOn-prem

Cloud & SaaS / container-orchestration

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique

Collection

View detailed technique mapping

References

https://github.com/projectcontour/contour/security/advisories/GHSA-g3xr-5w5j-w4q4

github.com

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-50149 and every CVE in our database. Create a free account — no credit card required.

Create Free Account

Plain-language analysis

Impact assessment and exploitation scenario in plain English

Attack graph visualization

Interactive attack path and kill chain mapping

Exploit details & PoC links

ExploitDB, Metasploit, GitHub PoCs with direct links

Nuclei scanner templates

Ready-to-use vulnerability scanner templates

Full remediation guide

Patch instructions, workarounds, and compliance impact

Interactive AI chat

Ask questions about this vulnerability in natural language

Related vulnerabilities

Semantically similar CVEs and attack patterns

REST API & MCP access

Integrate vulnerability data into your workflows