CVE-2026-87742 Quarkus-websockets-next: denial of service (oom) in quarkus-websockets-next via unbounded message buffering
Remote attackers can crash the JVM by flooding a WebSocket connection, causing an OutOfMemoryError due to unbounded message buffering in Quarkus.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-87742?
CVE-2026-87742 is a high-severity denial of service vulnerability in Red Hat Exploit Intelligence, published on 17 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 quarkus-websockets-next. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by streaming messages over a single connection faster than the application can process them. Due to unbounded message buffering and a lack of read backpressure, this rapidly exhausts heap space, leading to a java.lang.OutOfMemoryError that crashes the Java Virtual Machine (JVM).
Weakness: CWE-770
Which versions are affected by CVE-2026-87742?
How do I fix CVE-2026-87742?
No fix has been published for CVE-2026-87742 yet. Limit exposure of the affected software until one is available.
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-2026-87742 being exploited?
There is no known exploitation of CVE-2026-87742 in the wild and no public exploit code.
Sources
Also known as GHSA-g4x4-8j33-p4h3.