CVE-2026-33871
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of service disruption.
- Exploit odds
- 1.3% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 1.3% in the next 30 days (EPSS).
- Severity: 8.7 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 1.3% · EPSS, next 30 days
- Weakness
- CWE-770 · Allocation without limits
- Record status
- Modified
Affected
- Netty < 4.1.132
- Netty < 4.2.10
Attack profile CVSS 4.0 · 8.7
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
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
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-33871.md and follow it. Check whether this project is affected by CVE-2026-33871. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
References
- https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv
- https://access.redhat.com/errata/RHSA-2026:10175
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/errata/RHSA-2026:13571
- https://access.redhat.com/errata/RHSA-2026:14272
- https://access.redhat.com/errata/RHSA-2026:14276
- https://access.redhat.com/errata/RHSA-2026:17668
- https://access.redhat.com/errata/RHSA-2026:17789
- https://access.redhat.com/errata/RHSA-2026:18054
- https://access.redhat.com/errata/RHSA-2026:18055
- https://access.redhat.com/errata/RHSA-2026:18059
- https://access.redhat.com/errata/RHSA-2026:22619
- https://access.redhat.com/errata/RHSA-2026:34608
- https://access.redhat.com/errata/RHSA-2026:65126
- https://access.redhat.com/errata/RHSA-2026:7109
- https://access.redhat.com/errata/RHSA-2026:7380
- https://access.redhat.com/errata/RHSA-2026:8159
- https://access.redhat.com/errata/RHSA-2026:8509
- 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