CVE-2026-50149
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.
Statement
A flaw was found in Contour. When an HTTPProxy combines enableFallbackCertificate with jwtProviders, requests without TLS SNI bypass JWT verification and are proxied without a valid token.
Mitigation
Upgrade to Contour v1.33.5 or later. As a workaround, do not enable enableFallbackCertificate on HTTPProxy resources that also define jwtProviders.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
Understanding the Weakness (CWE)
Integrity,Authentication
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity
When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. The product might connect to a malicious host while believing it is a trusted host, or the product might be deceived into accepting spoofed data that appears to originate from a trusted host.
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