---
id: CVE-2023-45288
aliases:
  - GHSA-4v7x-pqxf-cx7m
  - BIT-golang-2023-45288
  - GO-2024-2687
title: 'net/http, x/net/http2: close connections when receiving too many headers'
summary: 'net/http, x/net/http2: close connections when receiving too many headers'
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
vendor: net
product: net/http
ecosystem: go
affected:
  - net/http < 1.21.9
  - golang.org/x/net/http2 < 0.23.0
  - 'net/http >= 1.22.0-0, < 1.22.2'
  - golang.org/x/net < 0.23.0
patched:
  - net/http 1.21.9
  - golang.org/x/net/http2 0.23.0
  - net/http 1.22.2
  - golang.org/x/net 0.23.0
published: '2024-04-04'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:11.106451165Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-4v7x-pqxf-cx7m'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2023-45288'
  - url: 'https://go.dev/cl/576155'
  - url: 'https://go.dev/issue/65051'
  - url: 'https://groups.google.com/g/golang-announce/c/YgW0sx8mN3M'
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QRYFHIQ6XRKRYBI2F5UESH67BJBQXUPT
  - url: 'https://nowotarski.info/http2-continuation-flood-technical-details'
  - url: 'https://pkg.go.dev/vuln/GO-2024-2687'
  - url: 'https://security.netapp.com/advisory/ntap-20240419-0009'
  - url: 'https://www.kb.cert.org/vuls/id/421644'
  - url: 'http://www.openwall.com/lists/oss-security/2024/04/03/16'
  - url: 'http://www.openwall.com/lists/oss-security/2024/04/05/4'
tags:
  - osv
  - go
  - exploit-available
epss: 0.91969
epssPercentile: 0.99817
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/hex0punk/cont-flood-poc'
  checkedAt: '2026-09-25T08:20:42.568Z'
exploitAvailable: true
ingestedAt: '2026-09-12T03:13:01.753Z'
---

## Overview

An attacker may cause an HTTP/2 endpoint to read arbitrary amounts of header data by sending an excessive number of CONTINUATION frames. Maintaining HPACK state requires parsing and processing all HEADERS and CONTINUATION frames on a connection. When a request's headers exceed MaxHeaderBytes, no memory is allocated to store the excess headers, but they are still parsed. This permits an attacker to cause an HTTP/2 endpoint to read arbitrary amounts of header data, all associated with a request which is going to be rejected. These headers can include Huffman-encoded data which is significantly more expensive for the receiver to decode than for an attacker to send. The fix sets a limit on the amount of excess header frames we will process before closing a connection.

## Affected packages

- `net/http < 1.21.9`
- `golang.org/x/net/http2 < 0.23.0`
- `net/http >= 1.22.0-0, < 1.22.2`
- `golang.org/x/net < 0.23.0`

## Remediation

Upgrade to a patched release:

- `net/http 1.21.9`
- `golang.org/x/net/http2 0.23.0`
- `net/http 1.22.2`
- `golang.org/x/net 0.23.0`