REDHAT-BUG-2477220: High severity Netty Netty vulnerability

Published May 13, 2026
·
Updated

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Affected Software

1 affected component
Netty Netty<4.2.13.Final, <4.1.133.Final

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade netty to a version that resolves this vulnerability.

    Fixed in 4.2.13.Final
  2. Upgrade

    Upgrade netty to a version that resolves this vulnerability.

    Fixed in 4.1.133.Final

Event History

May 13, 2026
Data Sourced
via Red Hat·07:01 PM
DescriptionSeverityAffected Software

Frequently Asked Questions

1

What is the severity of REDHAT-BUG-2477220?

The severity of REDHAT-BUG-2477220 is high, rated at 7.

2

How do I fix REDHAT-BUG-2477220?

To fix REDHAT-BUG-2477220, upgrade Netty to version 4.2.13.Final or 4.1.133.Final or later.

3

What is the risk associated with REDHAT-BUG-2477220?

The risk associated with REDHAT-BUG-2477220 is rated at 33.

4

What is the impact of the vulnerability REDHAT-BUG-2477220?

The impact of REDHAT-BUG-2477220 is related to the potential for decompression bomb attacks due to improper buffer size limitations.

5

Which versions of Netty are affected by REDHAT-BUG-2477220?

Versions of Netty prior to 4.2.13.Final and 4.1.133.Final are affected by REDHAT-BUG-2477220.

Contact

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