CVE-2026-93558

High CVSS 7.5

Published 2026-09-18 · last changed 2026-09-18

The fix

We hold no Microsoft remediation data for CVE-2026-93558, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

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.

Sources

NVD record for CVE-2026-93558

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H