# CVE-2026-33871

## Summary

- **CVE ID:** CVE-2026-33871
- **Severity:** HIGH
- **CVSS Score:** 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)
- **CWE:** CWE-770
- **Published:** Mar 27, 2026
- **Last Modified:** Sep 15, 2026

## Description

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server's lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

## Affected Products

- netty — netty (< 4.1.132.Final)
- netty — netty (>= 4.2.0.Alpha1, < 4.2.10.Final)

## References

- [CNA](https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv)
- [redhat-SADP](https://access.redhat.com/security/cve/CVE-2026-33871)
- [redhat-SADP](https://bugzilla.redhat.com/show_bug.cgi?id=2452456)
- [redhat-SADP](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33871.json)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18054)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17789)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18055)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:14276)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:14272)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:8509)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:8159)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22619)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18059)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:10184)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:10175)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17668)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:7109)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:7380)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:13571)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:34608)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:65126)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 1.13%
- **EPSS Percentile:** 64.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._