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Vulnerability · Published Jun 12, 2026 · Assigned by GitHub_M

CVE-2026-48043netty-codec-http2: ByteBuf Reference-Count Leak in DelegatingDecompressorFrameListener Leads to Memory Exhaustion

Medium 5.3

In plain English

A medium-severity uncontrolled resource consumption in netty from netty. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 55% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.8%top 44.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Netty is a network application framework for development of protocol servers and clients. In netty-codec-http2 prior to versions 4.1.135.Final and 4.2.15.Final, the `DelegatingDecompressorFrameListener` class orchestrates HTTP/2 decompression by embedding a per-stream `EmbeddedChannel` that runs the appropriate decompression codec (gzip, deflate, zstd) and forwards decompressed chunks to a wrapped listener. Each decompressed chunk is a pooled `ByteBuf` handed to an anonymous `ChannelInboundHandlerAdapter` tail handler, which becomes the sole owner responsible for releasing it. A remote peer could send frames that would result in the flow-controller throwing and so trigger a resource leak which at the end might take down the whole JVM due OOME. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12nettyno fix listedDEBIAN-CVE-2026-48043
Debian:13nettyno fix listedDEBIAN-CVE-2026-48043
Debian:14nettyno fix listedDEBIAN-CVE-2026-48043
Mavenio.netty:netty-codec-http24.2.15.FinalGHSA-c2gf-v879-257j
Mavenio.netty:netty-codec-http24.1.135.FinalGHSA-c2gf-v879-257j
Ubuntu:25.10nettyno fix listedUBUNTU-CVE-2026-48043
Ubuntu:26.10nettyno fix listedUBUNTU-CVE-2026-48043

Affected products (as reported)

VendorProductVersions
netty netty >= 4.2.0.Final, < 4.2.15.Final< 4.1.135.Final

Weakness: CWE-400, CWE-401, CWE-772 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References