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Fencer Intel
low 3.7

CVE-2026-107284 json

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

published last mo. modified last mo. also EUVD-2026-94644

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

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.

Patch / fix

  • asynchttpclient_project async-http-client 2.16.1, 3.0.12

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-107284 updated cvss 3.7

org.asynchttpclient/async-http-client: async-http-client: Processing of unverified WebSocket frames via improper handshake validation

  • Red Hat Fuse 7 async-http-client 2.0.40
    affected: workaround, no fix planned “Out of support scope”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected products

  • AsyncHttpClient async-http-client

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity
  • CWE-670 Always-Incorrect Control Flow Implementation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.