CVE-2026-33871
Netty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass
- State
- Published
- Severity
- 8.7 High
- Published
- Mar 27, 2026
- Updated
- Sep 15, 2026
- Reserved
- Mar 24, 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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | 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 | GitHub_M |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
Weaknesses
- CWE-770 Allocation of Resources Without Limits or Throttling
Affected Products
| Product | Versions |
|---|---|
nettynetty |
|
References
- https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv
- https://access.redhat.com/security/cve/CVE-2026-33871vdb-entry
- RHBZ#2452456issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33871.json
- https://access.redhat.com/errata/RHSA-2026:18054vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:17789vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:18055vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:14276vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:14272vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:8509vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:8159vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:22619vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:18059vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:10184vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:65126vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:10175vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:17668vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:7109vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:7380vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:34608vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:13571vendor-advisory
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