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Fencer Intel
high 8.1

CVE-2026-41246 json

Contour: Lua code injection via Cookie Path Rewrite Policy

published 6mo ago modified 14d ago also BIT-contour-2026-41246 , EUVD-2026-25280 , GHSA-x4mj-7f9g-29h4 , GO-2026-5738

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/projectcontour/contour 1.31.6, 1.32.5, 1.33.4
  • bitnami contour 1.31.6, 1.32.5, 1.33.4
  • projectcontour contour 1.31.6, 1.32.5, 1.33.4
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-41246 updated cvss 8.1

Contour: Envoy: github.com/projectcontour/contour: Contour: Arbitrary Code Execution and Denial of Service via Lua Code Injection

  • Red Hat ExternalDNS Operator edo/external-dns-rhel8, edo/external-dns-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6mo ago

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
CISA ADP 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
OSV 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/projectcontour/contour
>=1.19.0, <1.31.6
>=1.32.0, <1.32.5
>=1.33.0, <1.33.4
1.31.6
1.32.5
1.33.4
bitnami contour
>=1.19.0, <1.31.6
>=1.32.0, <1.32.5
>=1.33.0, <1.33.4
1.31.6
1.32.5
1.33.4

Affected products

  • projectcontour contour
  • Red Hat ExternalDNS Operator

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.