Security advisory

{
  "id": "3ff294f5e445c7a4121030b86163f547f4bd2ec8d71761b83e74eeefeaecc7d4",
  "url": "https://osv.dev/vulnerability/CVE-2020-11767",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-11767",
    "summary": "Istio through 1.5.1 and Envoy through 1.14.1 have a data-leak issue. If there is a TCP connection (negotiated with SNI over HTTPS) to *.example.com, a request for a domain concurrently configured explicitly (e.g., abc.example.com) is sent to the server(s) listening behind *.example.com. The outcome should instead be 421 Misdirected Request. Imagine a shared caching forward proxy re-using an HTTP/2 connection for a large subnet with many users. If a victim is interacting with abc.example.com, and a server (for abc.example.com) recycles the TCP connection to the forward proxy, the victim's browser may suddenly start sending sensitive data to a *.example.com server. This occurs because the forward proxy between the victim and the origin server reuses connections (which obeys the specification), but neither Istio nor Envoy corrects this by sending a 421 error. Similarly, this behavior voids the security model browsers have put in place between domains.",
    "evidence": "osv:CVE-2020-11767",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2020-11767",
      "aliases": [
        "BIT-envoy-2020-11767",
        "CVE-2020-11767"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/envoyproxy/envoy",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "3504d40f752eb5c20bc2883053547717bcb92fd8"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "1.14.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.14.1",
            "v1.14.0",
            "v1.13.0",
            "v1.12.0",
            "v1.11.0",
            "v1.10.0",
            "v1.9.0",
            "v1.8.0",
            "v1.7.0",
            "v1.6.0",
            "v1.5.0",
            "v1.4.0",
            "v1.3.0",
            "v1.2.0",
            "v1.1.0",
            "v1.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-11767.json"
          }
        },
        {
          "ranges": [
            {
              "repo": "https://github.com/istio/istio",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "9d07e185b0dd50e6fb1418caa4b4d879788807e3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:istio:istio:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "1.5.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.5.1",
            "1.5.0",
            "1.5.0-beta.5",
            "1.5.0-beta.4",
            "1.5.0-beta.3",
            "1.5.0-alpha.0",
            "1.2.0-rc.3",
            "1.2.0-rc.0",
            "1.1.0-snapshot.2",
            "1.1.0.snapshot.1",
            "1.1.0.snapshot.0",
            "1.0.0-snapshot.0",
            "0.6.0",
            "0.5.0",
            "0.3.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-11767.json"
          }
        }
      ],
      "modified": "2026-10-20T10:51:03.981106329Z",
      "provider": "osv",
      "references": [
        "https://github.com/envoyproxy/envoy/issues/6767",
        "https://github.com/istio/istio/issues/9429",
        "https://bugs.chromium.org/p/chromium/issues/detail?id=954160#c5",
        "https://github.com/istio/istio/issues/13589"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-11767",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 382461,
  "published_at": "2020-04-15T02:15:14+00:00"
}