Vulnerability · Published Apr 23, 2026 · Assigned by GitHub_M
CVE-2026-41246Contour: Lua code injection via Cookie Path Rewrite Policy
High 8.1
In plain English
A high-severity code injection in contour from projectcontour. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/projectcontour/contour | 1.31.6 | GHSA-x4mj-7f9g-29h4 |
| Go | github.com/projectcontour/contour | 1.32.5 | GHSA-x4mj-7f9g-29h4 |
| Go | github.com/projectcontour/contour | 1.33.4 | GHSA-x4mj-7f9g-29h4 |
| Go | github.com/projectcontour/contour | 1.31.6, 1.32.5, 1.33.4 | GO-2026-5738 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| projectcontour | contour | >= 1.33.0, < 1.33.4>= 1.32.0, < 1.32.5>= 1.19.0, < 1.31.6 |
Weakness: CWE-94 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
References
- https://github.com/projectcontour/contour/security/advisories/GHSA-x4mj-7f9g-29h4 x_refsource_CONFIRM
- https://github.com/projectcontour/contour/releases/tag/v1.31.6 x_refsource_MISC
- https://github.com/projectcontour/contour/releases/tag/v1.32.5 x_refsource_MISC
- https://github.com/projectcontour/contour/releases/tag/v1.33.4 x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-41246 vdb-entry, x_refsource_REDHAT
- RHBZ#2461257 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-41246.json x_sadp-csaf-vex