CVE-2026-48748Network attack vectorHinoki check available

JVM crash via unbounded QPACK blocked streams

Published Jun 12, 2026 · Updated Jun 12, 2026

Memory exhaustion in the Netty HTTP/3 codec 4.2.0.Final through 4.2.14.Final allows remote attackers to crash the JVM. QpackDecoder.shouldWaitForDynamicTableUpdates compares the count to maxBlockedStreams minus one, so a zero default never enforces the limit, while resumed entries remain retained. Reachability requires an HTTP/3 server with QPACK dynamic tables enabled and HTTP3_SETTINGS_QPACK_BLOCKED_STREAMS left at its zero default; crafted references then consume memory until the process crashes.

CVSS severity7.5
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
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Summary

What happened

Memory exhaustion in the Netty HTTP/3 codec 4.2.0.Final through 4.2.14.Final allows remote attackers to crash the JVM. QpackDecoder.shouldWaitForDynamicTableUpdates compares the count to maxBlockedStreams minus one, so a zero default never enforces the limit, while resumed entries remain retained. Reachability requires an HTTP/3 server with QPACK dynamic tables enabled and HTTP3_SETTINGS_QPACK_BLOCKED_STREAMS left at its zero default; crafted references then consume memory until the process crashes.

The record

CVE
CVE-2026-48748
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=>= 4.2.0.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

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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
T1499.004Application or System Exploitation

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

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Your stack

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