CVE-2026-73551

Description

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.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: MEDIUM
CVSS score: 5.3 / 10
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Effective score: 5.3 / 10 MEDIUM source: CNA overview
CWE(s): CWE-647
Reserved: 2026-08-12
Published: 2026-09-21 20:17 UTC
Last updated: 2026-09-21 20:17 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/73xxx/CVE-2026-73551.json

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-21 21:17:09 UTC
NVD last modified: 2026-09-21 21:17:09 UTC
NVD CVSS v3.1: 5.3 / 10 MEDIUM source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Exploitability subscore: 3.9 / 10
Impact subscore: 1.4 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84119
Assigner: GitHub_M
Published: Sep 21, 2026, 8:17:02 PM
Updated: Sep 21, 2026, 8:17:02 PM
EUVD base score (CVSS 3.1): 5.3 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EUVD-reported EPSS: 0.0000
Vendors: envoyproxy
Products: envoy (1.38.0, < 1.38.4)

envoy (1.39.0, < 1.39.1)

envoy (< 1.36.10)

envoy (1.37.0, < 1.37.6)

ENISA description: 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.

EUVD references (9)

Affected products (1)

Vendor	Product	Versions	Platforms
envoyproxy	envoy	`< 1.36.10` (affected), `>= 1.37.0, < 1.37.6` (affected), `>= 1.38.0, < 1.38.4` (affected), `>= 1.39.0, < 1.39.1` (affected)	—

Vendor references (9)

References embedded in the original CVE record by the assigning CNA.

https://github.com/envoyproxy/envoy/security/advisories/GHSA-2w8w-rfw7-8gg4 x_refsource_CONFIRM
https://github.com/envoyproxy/envoy/commit/28b6d60a6d96edeece121cac5be701eb46cc7f24 x_refsource_MISC
https://github.com/envoyproxy/envoy/commit/d40a68b0a30a003c4e0a9fd3af637f828b52c37b x_refsource_MISC
https://github.com/envoyproxy/envoy/commit/e9d6c329f9a3ff19432bf39b60c601df7e3eda33 x_refsource_MISC
https://github.com/envoyproxy/envoy/commit/f74d1107c4f5c9679b66f7a03a6c5b75ddde1989 x_refsource_MISC
https://github.com/envoyproxy/envoy/releases/tag/v1.36.10 x_refsource_MISC
https://github.com/envoyproxy/envoy/releases/tag/v1.37.6 x_refsource_MISC
https://github.com/envoyproxy/envoy/releases/tag/v1.38.4 x_refsource_MISC
https://github.com/envoyproxy/envoy/releases/tag/v1.39.1 x_refsource_MISC

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (9)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/envoyproxy/envoy/commit/28b6d60a6d96edeece121cac5be701eb46cc7f24 security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/d40a68b0a30a003c4e0a9fd3af637f828b52c37b security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/e9d6c329f9a3ff19432bf39b60c601df7e3eda33 security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/f74d1107c4f5c9679b66f7a03a6c5b75ddde1989 security-advisories@github.com
https://github.com/envoyproxy/envoy/releases/tag/v1.36.10 security-advisories@github.com
https://github.com/envoyproxy/envoy/releases/tag/v1.37.6 security-advisories@github.com
https://github.com/envoyproxy/envoy/releases/tag/v1.38.4 security-advisories@github.com
https://github.com/envoyproxy/envoy/releases/tag/v1.39.1 security-advisories@github.com
https://github.com/envoyproxy/envoy/security/advisories/GHSA-2w8w-rfw7-8gg4 security-advisories@github.com

Remediations (10)

CVEs and Security Vulnerabilities - OpenCVE

web:app.opencve.io

Explore the latest vulnerabilities and security issues in the CVE database

2026-09-22 17:10 UTC
Security Advisories and Bulletins | Microsoft Learn

web:learn.microsoft.com

In this library you will find the following security documents that have been released by the Microsoft Security Response Center (MSRC). The MSRC investigates all reports of security vulnerabilities affecting Microsoft products and services, and releases these documents as part of the ongoing effort to help you manage security risks and help keep your systems protected. Please use the ...

2026-09-22 17:10 UTC
Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-09-22 17:10 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-22 17:10 UTC
Description of the security update for Microsoft Exchange Server ...

web:support.microsoft.com

Description of the security update for Microsoft Exchange Server Subscription Edition RTM August 11, 2026 (KB5121573)

2026-09-22 17:10 UTC
SAP Security Patch Day - June 2026

web:support.sap.com

SAP security Patch Day Bulletin This post shares the information on security notes that remediate vulnerabilities discovered in SAP products. SAP strongly recommends that the customer visits the support portal and applies patches on priority to protect their SAP landscape. On 9th of June 2026 , SAP security patch day saw the release of 15 new security notes.

2026-09-22 17:10 UTC
DSA-2026-353: Security Update for Cloud Disaster Recovery ...

web:www.dell.com

Cloud Disaster Recovery remediation is available for multiple security vulnerabilities that could be exploited by malicious users to compromise the affected system.

2026-09-22 17:10 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-22 17:10 UTC
CVE-2026-73551: envoyproxy envoy: Envoy is an open source edge ... - Rapid7

web:www.rapid7.com

CVE-2026-73551 : envoyproxy envoy: Envoy is an open source edge and service proxy designed for cloud-native applications. View severity, references, and remediation details from Rapid7.

2026-09-22 17:10 UTC
Patch Tuesday September 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's September 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-09-22 17:10 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-73551.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "envoy",
          "vendor": "envoyproxy",
          "versions": [
            {
              "status": "affected",
              "version": "< 1.36.10"
            },
            {
              "status": "affected",
              "version": ">= 1.37.0, < 1.37.6"
            },
            {
              "status": "affected",
              "version": ">= 1.38.0, < 1.38.4"
            },
            {
              "status": "affected",
              "version": ">= 1.39.0, < 1.39.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-647",
              "description": "CWE-647: Use of Non-Canonical URL Paths for Authorization Decisions",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-21T20:17:02.620Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-2w8w-rfw7-8gg4",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-2w8w-rfw7-8gg4"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/28b6d60a6d96edeece121cac5be701eb46cc7f24",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/commit/28b6d60a6d96edeece121cac5be701eb46cc7f24"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/d40a68b0a30a003c4e0a9fd3af637f828b52c37b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/commit/d40a68b0a30a003c4e0a9fd3af637f828b52c37b"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/e9d6c329f9a3ff19432bf39b60c601df7e3eda33",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/commit/e9d6c329f9a3ff19432bf39b60c601df7e3eda33"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/f74d1107c4f5c9679b66f7a03a6c5b75ddde1989",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/commit/f74d1107c4f5c9679b66f7a03a6c5b75ddde1989"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/releases/tag/v1.36.10",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.36.10"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/releases/tag/v1.37.6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.37.6"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/releases/tag/v1.38.4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.38.4"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1"
        }
      ],
      "source": {
        "advisory": "GHSA-2w8w-rfw7-8gg4",
        "discovery": "UNKNOWN"
      },
      "title": "Envoy: Path normalization does not handle dot and dotdot segments with parameters"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-73551",
    "datePublished": "2026-09-21T20:17:02.620Z",
    "dateReserved": "2026-08-12T20:53:46.380Z",
    "dateUpdated": "2026-09-21T20:17:02.620Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}