Improper handling of highly compressed data in Async-http-client - #VU142452
Published: August 13, 2026
Vulnerability identifier: #VU142452
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-409
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper handling of highly compressed data in the HTTP/1.1 response decompressor when processing compressed response bodies with automatic decompression enabled. A remote attacker can send a small compressed response that expands without bound in memory to cause a denial of service.
gzip, deflate, and snappy are available vectors by default, while brotli and zstd apply only when the corresponding optional codecs are on the classpath.
Affected software
Async-http-client
Remediation
Install security update from vendor's website.
Async-http-client - addressed in versions 2.16.1, 3.0.12