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.
References10
- access.redhat.com/errata/RHSA-2026:69440
- access.redhat.com/errata/RHSA-2026:69470
- access.redhat.com/errata/RHSA-2026:70257
- access.redhat.com/errata/RHSA-2026:83612
- access.redhat.com/errata/RHSA-2026:95759
- access.redhat.com/errata/RHSA-2026:95760
- access.redhat.com/errata/RHSA-2026:95761
- access.redhat.com/errata/RHSA-2026:95762
- access.redhat.com/errata/RHSA-2026:95887
- access.redhat.com/security/cve/CVE-2026-93558
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 69 · as of 8 November 2026
- CWE
- CWE-1035
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.