---
id: CVE-2026-97031
title: >-
  Multiple ECH outer extension references are not permitted under RFC 9849;
  previously, a client could send a well-crafted packet that could trigger
  memory exhaustion in the server process by specifying multiple references
summary: >-
  Multiple ECH outer extension references are not permitted under RFC 9849;
  previously, a client could send a well-crafted packet that could trigger
  memory exhaustion in the server process by specifying multiple references. We
  now reject t…
severity: none
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T23:17:06.037'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97031'
references:
  - url: 'https://go.dev/cl/847312'
    label: security@golang.org
  - url: 'https://go.dev/issue/81855'
    label: security@golang.org
  - url: 'https://groups.google.com/g/golang-announce/c/U2fTuyDJznI'
    label: security@golang.org
  - url: 'https://pkg.go.dev/vuln/GO-2026-6607'
    label: security@golang.org
tags:
  - nvd
ingestedAt: '2026-10-09T00:19:50.981Z'
---

## Overview

Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references. We now reject these as malformed and curb the memory amplification vector as a result.

## Remediation

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