CVE-2026-93558
Io.netty/netty-codec-http: netty: unbounded per-connection queue growth in websocketserverextensionhandler leads to denial of service
Description
A flaw was found in Netty's WebSocketServerExtensionHandler. A remote, unauthenticated attacker can exploit this vulnerability by using HTTP/1.1 pipelining to send requests faster than the application can respond. This leads to an unbounded growth of a per-connection queue, consuming excessive memory. Eventually, this can cause the Java Virtual Machine (JVM) to exhaust its heap, resulting in a Denial of Service (DoS) for the affected server.
INFO
Published Date :
Sept. 18, 2026, 3:17 p.m.
Last Modified :
Sept. 22, 2026, 11:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-93558
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.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Implement connection-specific queue limits.
- Monitor and manage WebSocket connection queues.
- Apply updates to WebSocket handling components.
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-2026-93558.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-93558 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-2026-93558
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-2026-93558 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-93558 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.
-
CVE Modified by [email protected]
Sep. 22, 2026
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2026:69440 Added Reference https://access.redhat.com/errata/RHSA-2026:70257 -
CVE Modified by [email protected]
Sep. 21, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/93xxx/CVE-2026-93558.json">CVE-2026-93558</a> Added Reference https://access.redhat.com/errata/RHSA-2026:69470 -
CVE Modified by [email protected]
Sep. 18, 2026
Action Type Old Value New Value Changed Description Unbounded Per-Connection Queue Growth in WebSocketServerExtensionHandler Leads to Denial of Service A flaw was found in Netty's WebSocketServerExtensionHandler. A remote, unauthenticated attacker can exploit this vulnerability by using HTTP/1.1 pipelining to send requests faster than the application can respond. This leads to an unbounded growth of a per-connection queue, consuming excessive memory. Eventually, this can cause the Java Virtual Machine (JVM) to exhaust its heap, resulting in a Denial of Service (DoS) for the affected server. Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/93xxx/CVE-2026-93558.json">CVE-2026-93558</a> -
New CVE Received by [email protected]
Sep. 18, 2026
Action Type Old Value New Value Added Description Unbounded Per-Connection Queue Growth in WebSocketServerExtensionHandler Leads to Denial of Service Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-1035 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/93xxx/CVE-2026-93558.json">CVE-2026-93558</a> Added Reference https://access.redhat.com/security/cve/CVE-2026-93558 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2536932 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 18, 2026
Action Type Old Value New Value Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2536932 Added SSVC {'id': 'CVE-2026-93558', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-18T14:54:07.542588Z'}