CVE-2026-41246

What it is

Contour is a Kubernetes ingress controller using Envoy proxy. From v1.19.0 to before v1.33.4, v1.32.5, and v1.31.6, Contour's Cookie Rewriting feature is vulnerable to Lua code injection. An attacker with RBAC permissions to create or modify HTTPProxy resources can craft a malicious value in spec.routes[].cookieRewritePolicies[].pathRewrite.value or spec.routes[].services[].cookieRewritePolicies[].pathRewrite.value that results in arbitrary code execution in the Envoy proxy. The cookie rewriting feature is internally implemented using Envoy's HTTP Lua filter. User-controlled values are interpolated into Lua source code using Go text/template without sufficient sanitization. The injected code only executes when processing traffic on the attacker's own route, which they already control. However, since Envoy runs as shared infrastructure, the injected code can also read Envoy's xDS client credentials from the filesystem or cause denial of service for other tenants sharing the Envoy instance. This vulnerability is fixed in v1.33.4, v1.32.5, and v1.31.6.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure, service disruption.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-04-23 19:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 22:10 UTC Last updatedMost recent change to the record

Details

Published

2026-04-23 19:17 UTC

Last modified

2026-10-26 22:10 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-94 · Code injection

Record status

Modified

Affected

• Projectcontour Contour < 1.31.6
• Projectcontour Contour < 1.32.5
• Projectcontour Contour < 1.33.4

Attack profile CVSS 3.1 · 8.1

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High