CVE-2026-73552

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 HTTP RBAC accepts RFC-valid opaque header bytes but evaluates safe_regex values with RE2's UTF-8 subject semantics. A downstream client can preserve a prohibited marker and add an unrelated obs-text octet, causing RE2::FullMatch to return false and a negative RBAC policy to treat the invalid subject as an ordinary no-match. A byte-oriented route matcher can still observe the marker, allowing the request to reach a route intended to be denied. The relevant scope boundary is that plain positive ALLOW regexes normally fail closed, and exact, prefix, suffix, and contains matchers are not shown to have this subject-domain failure. 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: HIGH
CVSS score: 7.5 / 10
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Effective score: 7.5 / 10 HIGH source: CNA overview
CWE(s): CWE-20
Reserved: 2026-08-12
Published: 2026-09-21 19:37 UTC
Last updated: 2026-09-21 19:37 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/73xxx/CVE-2026-73552.json
Linked Threat: CVE-2026-73552 — Envoy: HTTP RBAC safe_regex can fail open on RFC-valid obs-text header values

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 20:17:28 UTC
NVD last modified: 2026-09-21 20:17:28 UTC
NVD CVSS v3.1: 7.5 / 10 HIGH source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Exploitability subscore: 3.9 / 10
Impact subscore: 3.6 / 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-2026-84104
Assigner: GitHub_M
Published: Sep 21, 2026, 7:37:20 PM
Updated: Sep 21, 2026, 7:37:20 PM
EUVD base score (CVSS 3.1): 7.5 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EUVD-reported EPSS: 0.0000
Vendors: envoyproxy
Products: envoy (< 1.36.10)

envoy (1.38.0, < 1.38.4)

envoy (1.39.0, < 1.39.1)

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 HTTP RBAC accepts RFC-valid opaque header bytes but evaluates safe_regex values with RE2's UTF-8 subject semantics. A downstream client can preserve a prohibited marker and add an unrelated obs-text octet, causing RE2::FullMatch to return false and a negative RBAC policy to treat the invalid subject as an ordinary no-match. A byte-oriented route matcher can still observe the marker, allowing the request to reach a route intended to be denied. The relevant scope boundary is that plain positive ALLOW regexes normally fail closed, and exact, prefix, suffix, and contains matchers are not shown to have this subject-domain failure. 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-23xh-2qxr-3xv8 x_refsource_CONFIRM
https://github.com/envoyproxy/envoy/commit/5650cb9770d4420ec2bcbed8b90be06f564ecc07 x_refsource_MISC
https://github.com/envoyproxy/envoy/commit/7d1dee5dda66434d84437cc5c85153aa03955e26 x_refsource_MISC
https://github.com/envoyproxy/envoy/commit/c2b9a19dc081f03be6a9b4ca932673e5e7a33d18 x_refsource_MISC
https://github.com/envoyproxy/envoy/commit/f3726765f3a12ddc76dcb52c0b79bec3d95ced1c 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/5650cb9770d4420ec2bcbed8b90be06f564ecc07 security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/7d1dee5dda66434d84437cc5c85153aa03955e26 security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/c2b9a19dc081f03be6a9b4ca932673e5e7a33d18 security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/f3726765f3a12ddc76dcb52c0b79bec3d95ced1c 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-23xh-2qxr-3xv8 security-advisories@github.com

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2026-73552 - Red Hat Customer Portal

web:access.redhat.com

What is a mitigation ? A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

2026-09-22 16:47 UTC
Security Updates - Red Hat Customer Portal

web:access.redhat.com

Learn about our open source products, services, and company. You are here

2026-09-22 16:47 UTC
July 2026 Critical Patch Update Released | security - Oracle Blogs

web:blogs.oracle.com

For more information about the Critical Patch Update program, see the security vulnerability remediation practices page located on the Oracle Trust Center.

2026-09-22 16:47 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 16:47 UTC
Cisco Advance Notification for Publication of September 16, 2026 ...

web:sec.cloudapps.cisco.com

On September 16, 2026 , the Cisco Product Security Incident Response Team (PSIRT) published the advisories that are listed in the following tables. To remediate these vulnerabilities, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories. For more information about changes in Cisco PSIRT vulnerability disclosure, see Strengthening the ...

2026-09-22 16:47 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 16:47 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 16:47 UTC
What Is CVE Remediation in 2026? - aikido.dev

web:www.aikido.dev

None of these is a clean fix , which is why the decision on how to remediate depends on knowing what package versions are running in production and why. This post will cover how AI has accelerated CVE detection and discovery, the upgrade trap, what CVE remediation actually involves in 2026 , and how to solve the CVE remediation problem.

2026-09-22 16:47 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 16:47 UTC
Oracle Critical Security Patch Update Advisory - June 2026

web:www.oracle.com

Additional CVEs addressed are: The patch for CVE - 2026 -34481 also addresses CVE - 2026 -34477, CVE - 2026 -34478, CVE - 2026 -34479, and CVE - 2026 -34480. Oracle Fusion Middleware Risk Matrix This Critical Security Patch Update contains 106 new security patches for Oracle Fusion Middleware. 53 of these vulnerabilities may be remotely exploitable without authentication, i.e., may be exploited over a ...

2026-09-22 16:47 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-73552.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"
            }
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        }
      ],
      "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 HTTP RBAC accepts RFC-valid opaque header bytes but evaluates safe_regex values with RE2's UTF-8 subject semantics. A downstream client can preserve a prohibited marker and add an unrelated obs-text octet, causing RE2::FullMatch to return false and a negative RBAC policy to treat the invalid subject as an ordinary no-match. A byte-oriented route matcher can still observe the marker, allowing the request to reach a route intended to be denied. The relevant scope boundary is that plain positive ALLOW regexes normally fail closed, and exact, prefix, suffix, and contains matchers are not shown to have this subject-domain failure. 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": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
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          "descriptions": [
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              "cweId": "CWE-20",
              "description": "CWE-20: Improper Input Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-21T19:37:20.546Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-23xh-2qxr-3xv8",
          "tags": [
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          ],
          "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-23xh-2qxr-3xv8"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/5650cb9770d4420ec2bcbed8b90be06f564ecc07",
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          "url": "https://github.com/envoyproxy/envoy/commit/5650cb9770d4420ec2bcbed8b90be06f564ecc07"
        },
        {
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          ],
          "url": "https://github.com/envoyproxy/envoy/commit/c2b9a19dc081f03be6a9b4ca932673e5e7a33d18"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/f3726765f3a12ddc76dcb52c0b79bec3d95ced1c",
          "tags": [
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          ],
          "url": "https://github.com/envoyproxy/envoy/commit/f3726765f3a12ddc76dcb52c0b79bec3d95ced1c"
        },
        {
          "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"
        },
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          "tags": [
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          ],
          "url": "https://github.com/envoyproxy/envoy/releases/tag/v1.39.1"
        }
      ],
      "source": {
        "advisory": "GHSA-23xh-2qxr-3xv8",
        "discovery": "UNKNOWN"
      },
      "title": "Envoy: HTTP RBAC safe_regex can fail open on RFC-valid obs-text header values"
    }
  },
  "cveMetadata": {
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    "datePublished": "2026-09-21T19:37:20.546Z",
    "dateReserved": "2026-08-12T20:53:46.380Z",
    "dateUpdated": "2026-09-21T19:37:20.546Z",
    "state": "PUBLISHED"
  },
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}