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PatchSiren cyber security CVE debrief

CVE-2026-44894 netty CVE debrief

CVE-2026-44894 is a vulnerability in Netty's NoQuicTokenHandler. Prior to version 4.2.15.Final, it incorrectly validates tokens, allowing an attacker to bypass the 3× anti-amplification send limit. This could lead to a high-impact attack, with a CVSS score of 7.5.

Vendor
netty
Product
Unknown
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-12
Original CVE updated
2026-07-15
Advisory published
2026-06-12
Advisory updated
2026-07-15

Who should care

Users of Netty prior to version 4.2.15.Final should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The NoQuicTokenHandler in Netty, used when no token handler is set, incorrectly validates tokens. The `writeToken()` method returns false, indicating the server will not send a Retry, but the `validateToken()` method unconditionally returns 0. This causes the server to treat the client's address as validated, lifting the 3× anti-amplification send limit. An attacker can exploit this by including any non-empty token bytes in an Initial packet with a spoofed victim source IP, causing the server to reflect full-size handshake flights towards the victim without the 3× cap.

Defensive priority

High

Recommended defensive actions

  • Upgrade to Netty version 4.2.15.Final or later.
  • Review and update any custom token handlers to ensure correct validation.

Evidence notes

This vulnerability was patched in Netty version 4.2.15.Final. For more information, see [ref-4](https://github.com/netty/netty/releases/tag/netty-4.2.15.Final) and [ref-5](https://github.com/netty/netty/security/advisories/GHSA-cmm3-54f8-px4j).

Sources and references

Verified primary and authoritative sources

  • CVE-2026-44894 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-44894

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

  • CVE-2026-44894 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-44894

    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.