{"cve":"CVE-2021-32783","nvd":{"published":"2021-07-23T22:15:08.480","modified":"2026-06-17T03:53:37.367","status":"Modified","description":"Contour is a Kubernetes ingress controller using Envoy proxy. In Contour before version 1.17.1 a specially crafted ExternalName type Service may be used to access Envoy's admin interface, which Contour normally prevents from access outside the Envoy container. This can be used to shut down Envoy remotely (a denial of service), or to expose the existence of any Secret that Envoy is using for its configuration, including most notably TLS Keypairs. However, it *cannot* be used to get the *content* of those secrets. Since this attack allows access to the administration interface, a variety of administration options are available, such as shutting down the Envoy or draining traffic. In general, the Envoy admin interface cannot easily be used for making changes to the cluster, in-flight requests, or backend services, but it could be used to shut down or drain Envoy, change traffic routing, or to retrieve secret metadata, as mentioned above. The issue will be addressed in Contour v1.18.0 and a cherry-picked patch release, v1.17.1, has been released to cover users who cannot upgrade at this time. For more details refer to the linked GitHub Security Advisory.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H","score":8.5},"cwes":["CWE-610","CWE-441"],"references":["https://github.com/projectcontour/contour/commit/b53a5c4fd927f4ea2c6cf02f1359d8e28bef852e","https://github.com/projectcontour/contour/releases/tag/v1.17.1","https://github.com/projectcontour/contour/security/advisories/GHSA-5ph6-qq5x-7jwc","https://github.com/projectcontour/contour/commit/b53a5c4fd927f4ea2c6cf02f1359d8e28bef852e","https://github.com/projectcontour/contour/releases/tag/v1.17.1"],"products":["projectcontour:contour"],"source":"nvd","synced_at":"2026-10-19T21:21:13.713336758+00:00"},"epss":{"cve":"CVE-2021-32783","score":0.01151,"percentile":0.6692,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-5ph6-qq5x-7jwc","url":"https://osv.dev/vulnerability/GHSA-5ph6-qq5x-7jwc","summary":"ExternalName Services can be used to gain access to Envoy's admin interface","modified":"2026-07-08T06:27:38.650773001Z","packages":[{"ecosystem":"Go","name":"github.com/projectcontour/contour","purl":"pkg:golang/github.com/projectcontour/contour","ranges":["<1.14.2"],"fixed":["1.14.2"]},{"ecosystem":"Go","name":"github.com/projectcontour/contour","purl":"pkg:golang/github.com/projectcontour/contour","ranges":[">=1.15.0 <1.15.2"],"fixed":["1.15.2"]},{"ecosystem":"Go","name":"github.com/projectcontour/contour","purl":"pkg:golang/github.com/projectcontour/contour","ranges":[">=1.16.0 <1.16.1"],"fixed":["1.16.1"]},{"ecosystem":"Go","name":"github.com/projectcontour/contour","purl":"pkg:golang/github.com/projectcontour/contour","ranges":[">=1.17.0 <1.17.1"],"fixed":["1.17.1"]}]},{"id":"GO-2022-0922","url":"https://osv.dev/vulnerability/GO-2022-0922","summary":"ExternalName Services can be used to gain access to Envoy's admin interface in github.com/projectcontour/contour","modified":"2026-03-03T04:51:03.769349Z","packages":[{"ecosystem":"Go","name":"github.com/projectcontour/contour","purl":"pkg:golang/github.com/projectcontour/contour","ranges":["<1.14.2",">=1.15.0 <1.15.2",">=1.16.0 <1.16.1",">=1.17.0 <1.17.1"],"fixed":["1.14.2","1.15.2","1.16.1","1.17.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}