Netty: HTTP/2 decompression leaks ByteBuf reference count when the decompressor channel is already closed (Direct memory leak / OOM DoS)

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-56819
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-21 23:17:52 UTC
Updated2026-07-22 20:35:40 UTC
DescriptionNetty 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

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

EPSS: 0.006300000 probability, percentile 0.464270000 (date 2026-07-22)

Problem Types: CWE-400 | CWE-401 | CWE-400 CWE-400: Uncontrolled Resource Consumption | CWE-401 CWE-401: Missing Release of Memory after Effective Lifetime

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Netty Netty affected >= 4.2.0.Final, < 4.2.16.Final Not specified
CNA Netty Netty affected >= 4.1.0.Final, < 4.1.136.Final Not specified

References

ReferenceSourceLinkTags
github.com/netty/netty/releases/tag/netty-4.1.136.Final [email protected] github.com
github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b [email protected] github.com
github.com/netty/netty/releases/tag/netty-4.2.16.Final [email protected] github.com
github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 [email protected] github.com
github.com/netty/netty/security/advisories/GHSA-93wv-jw9v-4972 [email protected] github.com
github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003bht... MITRE github.com
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