Memory leak in Netty - CVE-2026-56818

Vulnerability identifier: #VU140941

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-56818

CWE-ID: CWE-401

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to retain partial aggregate state and cause integrity and availability impacts.

The vulnerability exists due to improper handling of exceptional conditions in RedisArrayAggregator when processing a RESP array header that exceeds the configured maxElements limit. A remote attacker can send a specially crafted Redis message sequence to retain partial aggregate state and cause integrity and availability impacts.

Exploitation requires the application to keep the channel alive after the decoder exception so that later messages are consumed into the stale aggregate state.

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-p9jm-q85p-7mcp

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