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CVE-2026-73552

📛 CVE Title

Envoy: HTTP RBAC safe_regex can fail open on RFC-valid obs-text header values

⬇ Download JSON ⚠ View as Threat

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
CVSS 7.5 / 10 7.5 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
CVSS 7.5 / 10 7.5 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

NVD / KEV / EPSS data refreshed 2026-09-22 03:38 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.

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)
VendorProductVersionsPlatforms
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.

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.

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"
            }
          ]
        }
      ],
      "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": [
        {
          "descriptions": [
            {
              "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": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-23xh-2qxr-3xv8"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/5650cb9770d4420ec2bcbed8b90be06f564ecc07",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/commit/5650cb9770d4420ec2bcbed8b90be06f564ecc07"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/7d1dee5dda66434d84437cc5c85153aa03955e26",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/commit/7d1dee5dda66434d84437cc5c85153aa03955e26"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/c2b9a19dc081f03be6a9b4ca932673e5e7a33d18",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/envoyproxy/envoy/commit/c2b9a19dc081f03be6a9b4ca932673e5e7a33d18"
        },
        {
          "name": "https://github.com/envoyproxy/envoy/commit/f3726765f3a12ddc76dcb52c0b79bec3d95ced1c",
          "tags": [
            "x_refsource_MISC"
          ],
          "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"
        },
        {
          "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-23xh-2qxr-3xv8",
        "discovery": "UNKNOWN"
      },
      "title": "Envoy: HTTP RBAC safe_regex can fail open on RFC-valid obs-text header values"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-73552",
    "datePublished": "2026-09-21T19:37:20.546Z",
    "dateReserved": "2026-08-12T20:53:46.380Z",
    "dateUpdated": "2026-09-21T19:37:20.546Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}