🛡️ CVE-2026-47244 — netty

🟡 CVSS 5.3 — Medium ✅ No Known Exploit CWE-400 NVD

5.3

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability low.

Weakness class

CVE-2026-47244 is classified as CWE-400: Uncontrolled Resource Consumption. A request can consume memory, CPU or storage without limit, exhausting capacity for everyone else.

Affected software

CVE-2026-47244 is recorded against 3 packages.

io.netty:netty-codec-http2 (fixed in 4.1.135.Final)
netty (from 4.2.0 up to 4.2.15)
unknown

Timeline and source

Published on 8 June 2026 and last revised on 12 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Package)
github.com (Web)
github.com (Web)

CVE-2026-47244 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Debian

Details

Severity Medium

CVSS Score 5.3

CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CWE CWE-400

Public Exploit ✅ No

Source NVD

Published 2026-06-08

Updated 2026-08-12

Modified 2026-06-12

Fix URL N/A

Affected Packages

Software	From version	Fixed in
io.netty:netty-codec-http2	—	4.1.135.Final
netty	4.2.0	4.2.15
unknown	—	—

References

WEB https://github.com/netty/netty/security/advisories/GHSA-5x3r-wrvg-rp6q

ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-47244

PACKAGE https://github.com/netty/netty

WEB https://github.com/netty/netty/releases/tag/netty-4.1.135.Final

WEB https://github.com/netty/netty/releases/tag/netty-4.2.15.Final

🔗 NVD 🔗 Mitre

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