What’s Vulnerable › Vulnerabilities

CVE-2026-107284: AsyncHttpClient: WebSocket handshake continues after a failed Sec-WebSocket-Accept check

• Severity: low (CVSS 3.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% 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-345

Description

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Prior to 3.0.12 and 2.16.1, WebSocketHandler.upgrade aborts a handshake whose Sec-WebSocket-Accept value is missing or invalid but continues into pipeline installation and onOpen delivery. Frames coalesced with the invalid 101 response can be decoded and delivered from a peer that did not prove the handshake, although the request future fails and the channel closes. This issue is fixed in versions 3.0.12 and 2.16.1.

Affected products

• AsyncHttpClient async-http-client: from 3.0.0, < 3.0.12; from 2.0.0, < 2.16.1

References

• https://github.com/AsyncHttpClient/async-http-client/commit/75a278550aa9a980009d022fb4e635f9c8738c03
• https://github.com/AsyncHttpClient/async-http-client/commit/ccdcaa627db6d96dcc42105212cb3ba5048bd7f9
• https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.16.1
• https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.12
• https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-rwhr-j9rv-85f8

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