VulnerabilityModified

CVE-2026-41246

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.

HIGH 8.1EPSS 0.49%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.49%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1: 8.1 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
EPSS: 0.49% probability · 41th percentile
CISA KEV: Not listed
Weakness: CWE-94
Affected: projectcontour/contour
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.