CVE-2026-56819
Received
Received - Intake
Netty HTTP/2 Data Frame Memory Leak via DelegatingDecompressorFrameListener
Vulnerability report for CVE-2026-56819, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-07-21
Last updated on: 2026-07-21
Assigner: GitHub, Inc.
Description
Description
Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, a remote unauthenticated peer can leak one direct `ByteBuf` per HTTP/2 `DATA` frame in applications that enable HTTP/2 content decompression via `DelegatingDecompressorFrameListener`. When a `DATA` frame is processed for a stream whose decompressor has already been closed, `Http2Decompressor.decompress(...)` calls `decompressor.writeInbound(data.retain())` and does not release the retained buffer on the error path, eventually exhausting direct memory and crashing the JVM. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| netty | netty | From 4.1.0.Final (inc) to 4.1.135.Final (inc) |
| netty | netty | From 4.2.0.Final (inc) to 4.2.15.Final (inc) |
| netty | netty | 4.1.136.Final |
| netty | netty | 4.2.16.Final |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-400 | The product does not properly control the allocation and maintenance of a limited resource. |
| CWE-401 | The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse. |
