---
id: CVE-2026-73512
title: >-
  Envoy is an open source edge and service proxy designed for cloud-native
  applications
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
  HttpDatagramHandler caches the current RequestDecoder when Capsule Protocol is
  enabled. Stream r…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-416
vendor: envoyproxy
product: envoy
affected:
  - envoy < 1.36.10
  - 'envoy >= 1.37.0, < 1.37.6'
  - 'envoy >= 1.38.0, < 1.38.4'
  - 'envoy >= 1.39.0, < 1.39.1'
published: '2026-09-21'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T18:43:37.403'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73512'
references:
  - url: >-
      https://github.com/envoyproxy/envoy/commit/29dbaae4a9971011e2f1948acfaf383296e901ea
    label: security-advisories@github.com
  - url: >-
      https://github.com/envoyproxy/envoy/commit/85495163fdc67364a5258bfe478c34a44f6428b4
    label: security-advisories@github.com
  - url: >-
      https://github.com/envoyproxy/envoy/commit/c0e46dabc3ac286bbe608e9274776555911aadb9
    label: security-advisories@github.com
  - url: >-
      https://github.com/envoyproxy/envoy/commit/f2417eec2ff49abe243d484ded916fbc2faca38d
    label: security-advisories@github.com
  - url: 'https://github.com/envoyproxy/envoy/releases/tag/v1.36.10'
    label: security-advisories@github.com
  - url: 'https://github.com/envoyproxy/envoy/releases/tag/v1.37.6'
    label: security-advisories@github.com
  - url: 'https://github.com/envoyproxy/envoy/releases/tag/v1.38.4'
    label: security-advisories@github.com
  - url: 'https://github.com/envoyproxy/envoy/releases/tag/v1.39.1'
    label: security-advisories@github.com
  - url: >-
      https://github.com/envoyproxy/envoy/security/advisories/GHSA-r6j2-mrm5-72mg
    label: security-advisories@github.com
  - url: >-
      https://github.com/envoyproxy/envoy/security/advisories/GHSA-r6j2-mrm5-72mg
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-73512.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-73512'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2512088'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-73512'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73512'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
epss: 0.00827
epssPercentile: 0.55586
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-22T13:27:27.772374Z'
ingestedAt: '2026-09-21T20:52:58.284Z'
---

## Overview

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 HttpDatagramHandler caches the current RequestDecoder when Capsule Protocol is enabled. Stream recreation, including an internal redirect, replaces the ActiveStream and updates EnvoyQuicServerStream but does not update the handler's cached pointer. A subsequent HTTP/3 datagram can call decodeData through the freed decoder, causing invalid virtual dispatch and a process crash. The relevant scope boundary is that hTTP/3 datagrams and Capsule Protocol must be enabled, and the request must enter a stream-recreation path such as an internal redirect. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-73512.json)