What’s Vulnerable › Vulnerabilities

CVE-2026-107227: AsyncHttpClient: Unbounded WebSocket permessage-deflate decompression enables a decompression-bomb denial of service when compression is enabled

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-07 · updated 2026-10-08
• Weakness: CWE-400

Description

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.2.0 until 3.0.14, WebSocket permessage-deflate decompression is unbounded when compression is enabled. The inbound pipeline aggregates compressed frames before WebSocketClientCompressionHandler inflates them, so webSocketMaxFrameSize and webSocketMaxBufferSize do not bound decompressed output. A malicious WebSocket peer can send a small compressed message that expands to a very large Netty buffer and exhausts JVM heap. This issue is fixed in version 3.0.14.

Affected products

• AsyncHttpClient async-http-client: from 3.0.0, < 3.0.14; from 2.2.0, <= 2.16.1

References

• https://github.com/AsyncHttpClient/async-http-client/commit/b61637f30327f314b7693418f12ce141ac6b2b30
• https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.14
• https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-x8v2-478q-2hvg

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