Memory leak in Netty - CVE-2026-56819

Vulnerability identifier: #VU137566

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-56819

CWE-ID: CWE-401

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in Http2Decompressor.decompress(...) in DelegatingDecompressorFrameListener when processing HTTP/2 DATA frames for a stream whose decompressor channel has already been closed. A remote attacker can send specially crafted HTTP/2 DATA frames to cause a denial of service.

Only applications that enable HTTP/2 content decompression via DelegatingDecompressorFrameListener are vulnerable.

Netty
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
Development Tools Module
SUSE Package Hub 15
netty-tcnative-debugsource
netty-tcnative
netty
netty-javadoc

Install security update from vendor's website.

Netty - addressed in versions 4.1.136, 4.2.16
netty-tcnative-debugsource - update to 2.0.80-150200.3.48.1
netty-tcnative - update to 2.0.80-150200.3.48.1
netty - update to 4.1.136-150200.4.53.1
netty-javadoc - update to 4.1.136-150200.4.53.1

• https://github.com/netty/netty/security/advisories/GHSA-93wv-jw9v-4972

• Multiple vulnerabilities in Netty
• SUSE update for netty, netty-tcnative