---
id: CVE-2026-85721
title: >-
  The AsyncHttpClient (AHC) library allows Java applications to easily execute
  HTTP requests and asynchronously process HTTP responses
summary: >-
  The AsyncHttpClient (AHC) library allows Java applications to easily execute
  HTTP requests and asynchronously process HTTP responses. From 2.0.0 until
  2.16.1 and 3.0.12, automatic response decompression on the HTTP/1.1 path uses
  ChannelM…
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-400
  - CWE-409
  - CWE-770
vendor: asynchttpclient
product: 'org.asynchttpclient:async-http-client'
affected:
  - 'org.asynchttpclient:async-http-client >= 3.0.0, <= 3.0.11'
  - 'org.asynchttpclient:async-http-client >= 2.0.0, <= 2.16.0'
patched:
  - 'org.asynchttpclient:async-http-client 3.0.12'
  - 'org.asynchttpclient:async-http-client 2.16.1'
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T18:17:12.087'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85721'
references:
  - url: >-
      https://github.com/AsyncHttpClient/async-http-client/commit/5ee2841cbf268bba4a200578be3938ccfc6cc6d6
    label: security-advisories@github.com
  - url: >-
      https://github.com/AsyncHttpClient/async-http-client/commit/663a1a91757904b22cfe37e2e6049f1f8ea6ae59
    label: security-advisories@github.com
  - url: >-
      https://github.com/AsyncHttpClient/async-http-client/commit/e1871a19972fb496be1b8ac6be11d79e22ff2162
    label: security-advisories@github.com
  - url: >-
      https://github.com/AsyncHttpClient/async-http-client/commit/e9f2f7423e0f6503f529656f2955a1317e56ba14
    label: security-advisories@github.com
  - url: >-
      https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-7grg-jcf7-rpmx
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-7grg-jcf7-rpmx'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-85721.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-85721'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2536136'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-85721'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85721'
tags:
  - nvd
  - ghsa
  - maven
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
aliases:
  - GHSA-7grg-jcf7-rpmx
ecosystem: maven
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-17T17:22:02.572840Z'
ingestedAt: '2026-09-17T16:21:47.713Z'
epss: 0.0063
epssPercentile: 0.47972
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/xiaoqiMikko/async-http-client-check'
  checkedAt: '2026-09-26T09:06:03.239Z'
exploitAvailable: true
---

## Overview

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, automatic response decompression on the HTTP/1.1 path uses ChannelManager.newHttpContentDecompressor() to install Http1ContentDecompressor without a cumulative output-size limit. A hostile or compromised server, or an attacker who can alter a response in transit, can send a small gzip, deflate, or snappy response that expands across chunks until the client exhausts its heap and raises OutOfMemoryError; brotli and zstd are also affected when their optional codecs are present. In versions 3.0.8 through 3.0.10, the HTTP/2 decompressor is also unbounded, so switching protocols does not mitigate the issue on those releases. A limit applied to each decode call is insufficient because the response can be delivered as many small chunks, so the fixed implementation tracks total decompressed bytes for the whole response. This issue is fixed in versions 2.16.1 and 3.0.12.

## Remediation

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

## Package advisory (CVE-2026-85721)

Affected packages:

- `org.asynchttpclient:async-http-client >= 3.0.0, <= 3.0.11`
- `org.asynchttpclient:async-http-client >= 2.0.0, <= 2.16.0`

Patched in:

- `org.asynchttpclient:async-http-client 3.0.12`
- `org.asynchttpclient:async-http-client 2.16.1`

Source: https://github.com/advisories/GHSA-7grg-jcf7-rpmx

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Fuse 7 · no fix planned: Red Hat Fuse 7 · updated 2026-09-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-85721.json)