Unauthenticated JVM crash via unbounded request queue
Published Sep 18, 2026 · Updated Sep 18, 2026
Denial of service in Netty's WebSocketServerExtensionHandler allows remote attackers to exhaust JVM heap through HTTP/1.1 pipelining. The handler appends one validExtensions entry for every inbound request but removes entries only as responses are written, leaving the per-connection queue unbounded. No authentication or completed WebSocket upgrade is required; servers using WebSocket compression can crash with an OutOfMemoryError.
Summary
What happened
Denial of service in Netty's WebSocketServerExtensionHandler allows remote attackers to exhaust JVM heap through HTTP/1.1 pipelining. The handler appends one validExtensions entry for every inbound request but removes entries only as responses are written, leaving the per-connection queue unbounded. No authentication or completed WebSocket upgrade is required; servers using WebSocket compression can crash with an OutOfMemoryError.
The record
- CVE
- CVE-2026-93558
- Published
- Sep 18, 2026
- Updated
- Sep 18, 2026
- Vendor
- Commonhaus Foundation
- Product
- Red Hat JBoss Enterprise Application Platform 7
- Classifications
- CWE-1035, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 18, 2026CVE publishedPublication date reported by the CVE source.
- Sep 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Public exploit references
- PocPipelineQueue.java proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Get started to see how Hinoki identifies affected software and validates exploitability in your environment.
Get started