CVE-2026-50009Network attack vector

Connection interruption via HMAC-derived reset tokens

Published Jun 12, 2026 · Updated Jun 12, 2026

Information exposure in Netty QUIC 4.2.0.Final through 4.2.14.Final allows man-in-the-middle attackers to interrupt QUIC connections. HmacSignQuicConnectionIdGenerator and HmacSignQuicResetTokenGenerator reuse one JVM-wide key, causing a rotated source connection ID to reveal the current ID's reset token. An attacker must observe QUIC headers after source-CID rotation and can then send a spoofed Stateless Reset datagram that abruptly closes the client-side connection.

CVSS severity4.8
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Information exposure in Netty QUIC 4.2.0.Final through 4.2.14.Final allows man-in-the-middle attackers to interrupt QUIC connections. HmacSignQuicConnectionIdGenerator and HmacSignQuicResetTokenGenerator reuse one JVM-wide key, causing a rotated source connection ID to reveal the current ID's reset token. An attacker must observe QUIC headers after source-CID rotation and can then send a spoofed Stateless Reset datagram that abruptly closes the client-side connection.

The record

CVE
CVE-2026-50009
Published
Jun 12, 2026
Updated
Jun 12, 2026
Vendor
The Netty Project
Product
Netty
Classifications
CWE-330, CWE-200, T1498
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 4.2.0.Final, < 4.2.15.Final

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Netty Project · Nettyversion=>= 4.2.0.Final, < 4.2.15.Final

Published CVSS scores

4.8GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-330Use of Insufficiently Random Values
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1498Network Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo