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PatchSiren cyber security CVE debrief

CVE-2026-50020 netty CVE debrief

CVE-2026-50020 is a vulnerability in Netty's HttpObjectDecoder. Prior to versions 4.1.135.Final and 4.2.15.Final, the decoder skips certain bytes, including non-CRLF control characters, which can lead to request-boundary confusion in pipelined or multiplexed transports. This vulnerability has a CVSS score of 5.3 and is classified as MEDIUM severity.

Vendor
netty
Product
Unknown
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-12
Original CVE updated
2026-06-15
Advisory published
2026-06-12
Advisory updated
2026-06-15

Who should care

Users of Netty versions prior to 4.1.135.Final and 4.2.15.Final should be aware of this vulnerability and take steps to upgrade to a patched version.

Technical summary

The HttpObjectDecoder in Netty skips certain bytes, including non-CRLF control characters, before reading the first request-line. This behavior goes beyond the robustness allowance specified in RFC 9112 §2.2 and can be exploited for request-boundary confusion.

Defensive priority

MEDIUM

Recommended defensive actions

  • Upgrade to Netty version 4.1.135.Final or 4.2.15.Final or later.
  • Review and update affected applications to ensure they are using a patched version of Netty.

Evidence notes

This vulnerability was patched in Netty versions 4.1.135.Final and 4.2.15.Final. See [ref-4](https://github.com/netty/netty/releases/tag/netty-4.1.135.Final), [ref-5](https://github.com/netty/netty/releases/tag/netty-4.2.15.Final), and [ref-6](https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4c) for more information.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-50020 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-50020

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-50020 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-50020

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.