CVE-2026-33871
Netty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass
At a glance
- Severity
- HIGH 8.7
- EPSS
- EPSS 1.15 % · percentile 67 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
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
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | HIGH 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 | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
| CVSS 4.0 | HIGH 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Weaknesses (CWE)
Advisories
- GHSA-w9fj-cfpg-grvv — Netty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass
European references
- ENISA EUVD · EUVD-2026-16790
- GCVE · GCVE-0-2026-33871
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1067 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1032 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0998 — Multiples vulnérabilités dans les produits SAP · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0986 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0933 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0810 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0773 — Multiples vulnérabilités dans les produits Atlassian · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0698 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0627 — Multiples vulnérabilités dans les produits Splunk · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0581 — Multiples vulnérabilités dans MongoDB · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0556 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0500 — Multiples vulnérabilités dans VMware Tanzu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0479 — Multiples vulnérabilités dans les produits Atlassian · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*< 4.1.132cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*≥ 4.2.0 < 4.2.10
Affected products
| Product | Versions |
|---|---|
| netty · netty | affected < 4.1.132.Final ; affected >= 4.2.0.Alpha1, < 4.2.10.Final |
References
- https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv
- https://access.redhat.com/security/cve/CVE-2026-33871
- https://bugzilla.redhat.com/show_bug.cgi?id=2452456
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33871.json
- https://access.redhat.com/errata/RHSA-2026:18054
- https://access.redhat.com/errata/RHSA-2026:17789
- https://access.redhat.com/errata/RHSA-2026:18055
- https://access.redhat.com/errata/RHSA-2026:14276
- https://access.redhat.com/errata/RHSA-2026:14272
- https://access.redhat.com/errata/RHSA-2026:8509
- https://access.redhat.com/errata/RHSA-2026:8159
- https://access.redhat.com/errata/RHSA-2026:22619
- https://access.redhat.com/errata/RHSA-2026:18059
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/errata/RHSA-2026:65126
- https://access.redhat.com/errata/RHSA-2026:10175
- https://access.redhat.com/errata/RHSA-2026:17668
- https://access.redhat.com/errata/RHSA-2026:7109
- https://access.redhat.com/errata/RHSA-2026:7380
- https://access.redhat.com/errata/RHSA-2026:34608
- https://access.redhat.com/errata/RHSA-2026:13571
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |