Envoy: Path normalization does not handle dot and dotdot segments with parameters

{
  "id": "729df31c8d7f5e8d8c9551e912cdaccab6a90de18e09e1e053133ee381c6d538",
  "url": "https://osv.dev/vulnerability/BIT-envoy-2026-73551",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Envoy: Path normalization does not handle dot and dotdot segments with parameters",
    "summary": "Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's URL normalization does not recognize dot and dotdot path segments when they carry semicolon parameters. A request such as /user/..;foo=bar/admin is therefore not canonicalized to /admin even when path normalization is enabled. If an upstream interprets the segment according to RFC 3986 while Envoy applies routing or RBAC to the uncollapsed path, a remote client can cause path confusion and bypass path-based security policy. The relevant scope boundary is that the security consequence depends on a downstream/upstream path interpretation mismatch or a path-based Envoy decision. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.",
    "evidence": "osv:BIT-envoy-2026-73551",
    "products": [
      {
        "name": {
          "value": "envoy",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.36.10",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.37.6",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.38.4",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.39.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "BIT-envoy-2026-73551",
      "aliases": [
        "BIT-envoy-2026-73551",
        "CVE-2026-73551",
        "GHSA-2w8w-rfw7-8gg4"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.36.10"
                },
                {
                  "introduced": "1.37.0"
                },
                {
                  "fixed": "1.37.6"
                },
                {
                  "introduced": "1.38.0"
                },
                {
                  "fixed": "1.38.4"
                },
                {
                  "introduced": "1.39.0"
                },
                {
                  "fixed": "1.39.1"
                }
              ]
            }
          ],
          "package": {
            "name": "envoy",
            "purl": "pkg:bitnami/envoy",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V3",
              "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/envoy/BIT-envoy-2026-73551.json"
          }
        }
      ],
      "modified": "2026-10-06T15:15:04.562355687Z",
      "provider": "osv",
      "references": [
        "https://github.com/envoyproxy/envoy/commit/28b6d60a6d96edeece121cac5be701eb46cc7f24",
        "https://github.com/envoyproxy/envoy/commit/d40a68b0a30a003c4e0a9fd3af637f828b52c37b",
        "https://github.com/envoyproxy/envoy/commit/e9d6c329f9a3ff19432bf39b60c601df7e3eda33",
        "https://github.com/envoyproxy/envoy/commit/f74d1107c4f5c9679b66f7a03a6c5b75ddde1989",
        "https://github.com/envoyproxy/envoy/releases/tag/v1.36.10",
        "https://github.com/envoyproxy/envoy/releases/tag/v1.37.6",
        "https://github.com/envoyproxy/envoy/releases/tag/v1.38.4",
        "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1",
        "https://github.com/envoyproxy/envoy/security/advisories/GHSA-2w8w-rfw7-8gg4",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-73551"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*"
        ],
        "severity": "Medium"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-73551",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 89115,
  "published_at": "2026-09-29T08:43:16.381+00:00"
}