CVE-2026-100658
Netty before 4.1.138.Final Denial of Service via WebSocketServerExtensionHandler
Description
Netty (io.netty:netty-codec-http) contains an unbounded per-connection queue in WebSocketServerExtensionHandler. The handler offers an entry to its per-channel validExtensions queue for every inbound HttpRequest, but polls an entry only when the application writes an HttpResponse, and the queue size is never bounded. A remote, unauthenticated peer can use HTTP/1.1 pipelining to send requests faster than the application produces responses — including plain non-upgrade HTTP requests to any path — causing the queue to grow without limit until the JVM exhausts heap memory and terminates with OutOfMemoryError. Because the affected handler is the base class of WebSocketServerCompressionHandler, any server that enables permessage-deflate is exposed on its plain HTTP port before any WebSocket upgrade completes and before any application-level authentication. Affected versions are 4.1.88.Final through 4.1.137.Final and 4.2.0.Final through 4.2.17.Final; the issue is fixed in 4.1.138.Final and 4.2.18.Final.
INFO
Published Date :
Sept. 26, 2026, 2:16 p.m.
Last Modified :
Sept. 26, 2026, 2:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-100658
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update to Netty 4.1.138.Final or later.
- Update to Netty 4.2.18.Final or later.
- Apply vendor patches promptly.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-100658.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-100658 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-100658
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-100658 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-100658 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Sep. 26, 2026
Action Type Old Value New Value Added Description Netty (io.netty:netty-codec-http) contains an unbounded per-connection queue in WebSocketServerExtensionHandler. The handler offers an entry to its per-channel validExtensions queue for every inbound HttpRequest, but polls an entry only when the application writes an HttpResponse, and the queue size is never bounded. A remote, unauthenticated peer can use HTTP/1.1 pipelining to send requests faster than the application produces responses — including plain non-upgrade HTTP requests to any path — causing the queue to grow without limit until the JVM exhausts heap memory and terminates with OutOfMemoryError. Because the affected handler is the base class of WebSocketServerCompressionHandler, any server that enables permessage-deflate is exposed on its plain HTTP port before any WebSocket upgrade completes and before any application-level authentication. Affected versions are 4.1.88.Final through 4.1.137.Final and 4.2.0.Final through 4.2.17.Final; the issue is fixed in 4.1.138.Final and 4.2.18.Final. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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 Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-770 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/100xxx/CVE-2026-100658.json">CVE-2026-100658</a> Added Reference https://github.com/netty/netty/security/advisories/GHSA-2g37-3h88-55hc Added Reference https://www.vulncheck.com/advisories/netty-before-4.1.138-final-denial-of-service-via-websocketserverextensionhandler