Medium 5.3Published Jun 12, 2026

CVE-2026-47244Netty is a network application framework for development of protocol servers and clients.

Updated under an hour ago (2026-10-19 09:00 UTC)

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Exploited in the last 30 days

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, DefaultHttp2Connection.DefaultEndpoint initialises maxActiveStreams/maxStreams to Integer.MAX_VALUE, and Http2Settings never inserts SETTINGS_MAX_CONCURRENT_STREAMS by default (Http2Settings.java:305-307 only clamps a user-supplied value). Unless the application explicitly calls initialSettings().maxConcurrentStreams(n), a Netty HTTP/2 server advertises no limit and enforces none locally. Each open stream allocates a DefaultStream object, PropertyMap slots, flow-controller state and IntObjectHashMap entry; with ~2^30 permissible odd stream IDs a single TCP connection can create hundreds of thousands of long-lived stream objects. This is also the precondition for CVE-2023-44487-style Rapid-Reset amplification, where the absence of a low concurrent cap multiplies backend work. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVSS: 5.3 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE): CWE-400
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Jun 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

netty netty netty:netty	before 4.1.135; from 4.2.0 before 4.2.15	NVD

References

https://github.com/netty/netty/releases/tag/netty-4.1.135.Finalrelease-notes
https://github.com/netty/netty/releases/tag/netty-4.2.15.Finalrelease-notes
https://github.com/netty/netty/security/advisories/GHSA-5x3r-wrvg-rp6qvendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.