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Low severity · published Oct 7, 2026
CVE-2026-107284
AsyncHttpClient: WebSocket handshake continues after a failed Sec-WebSocket-Accept check
3.7
CVSS
0.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 3% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AS
async-http-client · AsyncHttpClient
>= 3.0.0, < 3.0.12; >= 2.0.0, < 2.16.1 · source: vendor
Affected product
AS
async-http-client
AsyncHttpClient
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-107284
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-107284
x_refsource_CONFIRM
https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-rwhr-j9rv-85f8
x_refsource_MISC
https://github.com/AsyncHttpClient/async-http-client/commit/75a278550aa9a980009d022fb4e635f9c8738c03
x_refsource_MISC
https://github.com/AsyncHttpClient/async-http-client/commit/ccdcaa627db6d96dcc42105212cb3ba5048bd7f9
x_refsource_MISC
https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.16.1
x_refsource_MISC
https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.12
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