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OpenAdvisories
High · 7.5 Public exploit CVE-2026-85721 EUVD-2026-81907GHSA-7grg-jcf7-rpmx

AsyncHttpClient: Unbounded HTTP/1.1 response decompression enables a decompression-bomb denial of service

Published Sep 17, 2026 · Updated Sep 17, 2026 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
AsyncHttpClient async-http-client >= 2.0.0, < 2.16.1, >= 3.0.0, < 3.0.12 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 12 async-http-client No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 async-http-client No fix yet —
Ubuntu 26.04 LTS async-http-client No fix yet —
Ubuntu 24.04 LTS async-http-client No fix yet —
Ubuntu 22.04 LTS async-http-client No fix yet —
Ubuntu 18.04 LTS async-http-client No fix yet —
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 16.04 LTS async-http-client No fix yet —
Ubuntu Pro 20.04 LTS async-http-client No fix yet —
Ubuntu Pro 14.04 LTS async-http-client No fix yet —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling apache-pulsar-4.2 4.2.4-r4 —
Wolfi rolling druid 37.0.0-r58 —
Wolfi rolling tez 0.10.5-r31 —

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 1 repository

  • xiaoqiMikko/async-http-client-check ★ 0 · Sep 19, 2026

    CVE-2026-85721: offline checker for org.asynchttpclient:async-http-client against all 26 repository-level advisories. 3.x is fixed in 3.0.14. The 2.x line is end of life - its last release 2.16.1 is …

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

Affected packages

EcosystemPackageAffectedFixedRecord
Maven org.asynchttpclient:async-http-client >= 3.0.0, < 3.0.12 3.0.12 GHSA-7grg-jcf7-rpmx
Maven org.asynchttpclient:async-http-client >= 2.0.0, < 2.16.1 2.16.1 GHSA-7grg-jcf7-rpmx

References