# CVE-2026-47244: Netty uncontrolled resource consumption in HTTP/2 codec

Source: https://junglewise.ai/threats/cve-2026-47244-netty-uncontrolled-resource-consumption-in-http-2-codec  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-12. Updated: 2026-06-12  
License: CC BY 4.0 with a link back

CVE-2026-47244 · Severity: medium · CVSS 5.3 · Published 2026-06-12

Netty is a widely used networking framework for building Java applications. A vulnerability in its HTTP/2 implementation allows a remote attacker to open an unlimited number of streams on a single connection, consuming excessive server memory and processing power. This can lead to a denial-of-service (DoS) condition, making the application unavailable to legitimate users.

Technologies: [io.netty:netty-codec-http2 (Maven)](https://junglewise.ai/threats/technologies/io-netty-netty-codec-http2), [Netty Project Netty Codec HTTP2](https://junglewise.ai/threats/technologies/netty-codec-http2). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven), [Netty Project](https://junglewise.ai/threats/vendors/netty-project).

## Quick answers

**Is CVE-2026-47244 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-47244 being exploited in the wild.

**How severe is CVE-2026-47244?** Medium severity, with a CVSS score of 5.3, published 12 June 2026.

**Which products and versions are affected?** io.netty:netty-codec-http2 (Maven) ECOSYSTEM:introduced=4.2.0.Final,fixed=4.2.15.Final; Netty Project Netty Codec HTTP2 < 4.1.135.Final, 4.2.0.Final - 4.2.14.Final.

**Is there a fix for CVE-2026-47244?** Yes. io.netty:netty-codec-http2 (Maven): upgrade to 4.2.15.Final or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-47244 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-47244?** Check whether you run io.netty:netty-codec-http2 (Maven), Netty Project Codec HTTP/2 or Netty Project Netty Codec HTTP2 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- io.netty:netty-codec-http2 (Maven): upgrade to 4.2.15.Final or later

  ```sh
  # set io.netty:netty-codec-http2 to 4.2.15.Final in your pom.xml or build.gradle
  ```


## Technical details

The vulnerability exists in the DefaultHttp2Connection component where maxActiveStreams is initialized to Integer.MAX_VALUE by default. Because Http2Settings does not automatically insert a SETTINGS_MAX_CONCURRENT_STREAMS value, a Netty server may advertise and enforce no limit on concurrent streams unless explicitly configured by the developer. An attacker can exploit this by opening hundreds of thousands of long-lived stream objects (DefaultStream, PropertyMap, etc.) over a single TCP connection, leading to uncontrolled memory consumption (CWE-400). This lack of a concurrent cap also facilitates Rapid-Reset style amplification attacks. The issue is resolved in versions 4.1.135.Final and 4.2.15.Final.

## Affected products

- Netty netty-codec-http2 < 4.1.135.Final, 4.2.0.Final - 4.2.14.Final

## Identifiers

- CVE-2026-47244
- GHSA-5x3r-wrvg-rp6q

## Timeline

- 2026-06-02: patched: Versions 4.1.135.Final and 4.2.15.Final released
- 2026-06-05: advisory: GitHub Security Advisory published
- 2026-06-12: disclosed: CVE-2026-47244 published to NVD

## References

- [https://github.com/netty/netty/releases/tag/netty-4.1.135.Final](https://github.com/netty/netty/releases/tag/netty-4.1.135.Final)
- [https://github.com/netty/netty/releases/tag/netty-4.2.15.Final](https://github.com/netty/netty/releases/tag/netty-4.2.15.Final)
- [https://github.com/netty/netty/security/advisories/GHSA-5x3r-wrvg-rp6q](https://github.com/netty/netty/security/advisories/GHSA-5x3r-wrvg-rp6q)

## Related threats

- [Netty request smuggling via Host header duplication in HTTP/2 translation](https://junglewise.ai/threats/cve-2026-59900-netty-request-smuggling-via-host-header-duplication-in-http-2)
- [Netty memory leak in HTTP/2 content decompression](https://junglewise.ai/threats/cve-2026-56819-netty-memory-leak-in-http-2-content-decompression)
- [Netty denial of service in HTTP/2 codec via max header size handling](https://junglewise.ai/threats/cve-2026-50560-netty-denial-of-service-in-http-2-codec-via-max-header-size)
- [Netty memory exhaustion in DelegatingDecompressorFrameListener](https://junglewise.ai/threats/cve-2026-48043-netty-memory-exhaustion-in-delegatingdecompressorframelistener)
- [Netty denial of service via decompression limit bypass](https://junglewise.ai/threats/cve-2026-42587-netty-denial-of-service-via-decompression-limit-bypass)