CVE-2026-50560Network attack vector

Unauthenticated denial of service via tiny header limit

Published Jun 12, 2026 · Updated Jun 12, 2026

Denial of service in Netty before 4.1.135.Final and 4.2.0.Final through 4.2.14.Final allows remote attackers to interrupt HTTP/2 service. Netty honors a client's advisory SETTINGS_MAX_HEADER_LIST_SIZE value, so a tiny limit triggers an exception while response headers are written after the request reaches the origin. An unauthenticated HTTP/2 client can repeat this inexpensive failure to consume server resources and disrupt availability, without reading or altering data.

CVSS severity6.9
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Netty before 4.1.135.Final and 4.2.0.Final through 4.2.14.Final allows remote attackers to interrupt HTTP/2 service. Netty honors a client's advisory SETTINGS_MAX_HEADER_LIST_SIZE value, so a tiny limit triggers an exception while response headers are written after the request reaches the origin. An unauthenticated HTTP/2 client can repeat this inexpensive failure to consume server resources and disrupt availability, without reading or altering data.

The record

CVE
CVE-2026-50560
Published
Jun 12, 2026
Updated
Jun 12, 2026
Vendor
The Netty Project
Product
Netty
Classifications
CWE-770, T1499.004
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

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Is a vulnerable build present?

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

  1. Affected versionversion=< 4.1.135.Final
  2. 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=< 4.1.135.Final; version=>= 4.2.0.Final, < 4.2.15.Final

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
6.9GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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