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Advisory record · GHSA-93wv-jw9v-4972

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

CVSS 7.5 HighEPSS 0.0066 · 52nd percentile

Published by the GitHub Advisory Database at 31 Jul 2026, 16:51 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
io.netty:netty-codec-http2Maven>=4.2.0, <4.2.16.Final || >=4.1.0.Final, <4.1.136.Final4.2.16.Final, 4.1.136.Final
Identifiers
GHSA-93wv-jw9v-4972 · CVE-2026-56819
Weakness (CWE)
CWE-400 · CWE-401
Tags
Published
31 Jul 2026
Updated
10 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Netty's codec-http2 package is vulnerable in versions from 4.2.0 up to but not including 4.2.16.Final and from 4.1.0.Final up to but not including 4.1.136.Final. A remote, unauthenticated peer can send HTTP/2 DATA frames for a stream whose decompressor has already been closed, which leaks one direct ByteBuf per frame when HTTP/2 content decompression is enabled. Repeated over a long-lived connection, this can exhaust direct memory and crash the JVM with an OutOfMemoryError. Upgrade to 4.2.16.Final or 4.1.136.Final.

Written 2 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
7.5 High 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0066, the 52nd percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:16 UTC First seen by agentprime
  2. 31 Oct 2026, 14:16 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.