CVE-2026-59899

Netty HttpContentEncoder: Unbounded Per-Connection Queue Growth via HTTP/1.1 Pipelining Leads to Denial of Service

HIGH
7.5
CVSS Score
Published: July 29, 2026 at 06:00 PM UTC
Updated: August 6, 2026 at 08:40 PM UTC
1 product affected across 1 vendorNetty

Using netty by netty?

Get instant alerts when new vulnerabilities affect netty - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, `HttpContentEncoder` (the superclass of the production handler `HttpContentCompressor`) maintains a per-channel `ArrayDeque<CharSequence>` named `acceptEncodingQueue` that accumulates attacker-controlled data without any size limit. The queue is filled on the I/O thread for every inbound HTTP request and drained only when the application later writes a non-1xx response. This creates a resource exhaustion vulnerability when an attacker exploits HTTP/1.1 pipelining to flood the connection with requests faster than the application produces responses. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.1.136v < 4.1.136.Finalv < 4.2.16.Final4.2.0 ≤ v < 4.2.16
Affected range stops below 4.1.136, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.1.136.Final, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.16, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.16.Final, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/netty/netty/security/advisories/GHSA-q4f6-jm68-57ww
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-770

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card