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CVE-2026-33871 Netty

Affected softwareNetty
Severity8.7 High CVSS 4.0 3 scores
Fixed in4.1.132.Final, 4.2.11.Final
WeaknessCWE-770
Published27 Mar 2026
Updated14 Sep 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.

Exploitation status

No public exploit

No exploit has been reported in the sources we check.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment exploitation: none
  • Indexed PoC none indexed
  • EPSS 1.4% chance in 30 days

Waratek protection

No exploit published

Within Waratek scope. In the sources we check, nobody has published exploit code for this CVE or reported it being exploited.

A public code fix exists.

  • Protection none
  • Action unverified
  • Review automated Upstream data
  • Record active
Decided by Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all
Finding This CVE is not listed in CISA KEV or VulnCheck KEV, CISA Vulnrichment records no active exploitation, no reviewed exploit catalogue carries an entry for it, and no GitHub PoC repository for it has 5 or more stars. Nobody has published exploit code worth tracing, so it is not a candidate for a rule ahead of the ones where somebody has; an upstream fix path does exist, so the remediation half of the candidacy still holds. This is a statement about what has been published, not about whether the defect is reachable or serious.
Candidate fix https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv : the maintainers' own security advisory: names the version that fixes it, so the fix is the difference between two releases

CVSS

8.7 HIGH v4.0 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 3 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 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/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 security-advisories@github.com Secondary published
CVSS 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H NVD Primary
CVSS 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 Secondary

Affected software and releases

Oracle advisories

AdvisoryTypeQuarterProducts Oracle names in its risk matrix
Oracle Critical Patch Update July 2026 ↗ CPU 2026-Q3 Oracle GoldenGate / Security (Netty) (26.1.0.0.0)
Oracle GoldenGate / Third Party (Netty) (21.3-21.20, 23.4-23.26.1)

Oracle components and versions

FamilyComponentVersions, as Oracle lists themRead as
Oracle GoldenGate Security (Netty) 26.1.0.0.0 26.1.0.0.0
Oracle GoldenGate Third Party (Netty) 21.3-21.20, 23.4-23.26.1

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
io.netty:netty-codec-http2 0 4.1.132.Final unbounded
io.netty:netty-codec-http2 4.2.0.Alpha1 4.2.11.Final unbounded

Products and versions

2 products, 4 version entries
SourceVendorProductSchemeAffected versions
osv io.netty netty-codec-http2 generic < 4.1.132 · ≥ 4.2.0 and < 4.2.11
nvd netty netty generic < 4.1.132 · ≥ 4.2.0 and < 4.2.10

References

URLTags
https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv advisory
https://github.com/netty/netty PACKAGE
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

Timeline

Published2026-03-27By the CVE Program.
NVD record modified2026-09-14NVD's own last-modified date for this record.