CVE-2026-93488 Io.netty/netty-codec-http: netty: denial of service via unbounded concurrent spdy streams
Remote attackers can cause denial of service in Netty by opening unlimited SPDY streams, leading to memory exhaustion and JVM crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93488?
CVE-2026-93488 is a high-severity denial of service vulnerability in Red Hat AMQ Broker 7, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in Netty. SpdySessionHandler accepts an unlimited number of concurrent remote-initiated streams because localConcurrentStreams defaults to Integer.MAX_VALUE and the handler provides no API to change it. A remote peer can open a SPDY connection and send a large number of SYN_STREAM frames with FLAG_FIN=0, causing unbounded heap and direct memory allocation that can lead to JVM OutOfMemoryError and a denial of service.
Weakness: CWE-770
Which versions are affected by CVE-2026-93488?
How do I fix CVE-2026-93488?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-93488 being exploited?
There is no known exploitation of CVE-2026-93488 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-FL88614, CLEANSTART-2026-ZG30727, DEBIAN-CVE-2026-93488, GHSA-mrqx-2r72-2c2x, UBUNTU-CVE-2026-93488.