Input validation error in Netty - CVE-2026-59900

Vulnerability identifier: #VU137562

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:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-59900

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to bypass request routing controls.

The vulnerability exists due to improper input validation in Http2StreamFrameToHttpObjectCodec and InboundHttp2ToHttpAdapter when translating HTTP/2 HEADERS frames containing both the :authority pseudo-header and a literal host header. A remote attacker can send a specially crafted HTTP/2 request to bypass request routing controls.

The issue occurs because the translator maps :authority to Host and separately copies the literal host header, resulting in an HttpRequest object with two Host headers containing different attacker-controlled values.

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-c69g-56f8-xwqj

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