CVE-2026-81624 Undertow-core: undertow: websocketcontainer defaults for buffers and timeouts are infinite
Remote attackers can crash the Undertow web server by exhausting resources due to unlimited WebSocket buffer and timeout defaults.
- 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-2026-81624?
CVE-2026-81624 is a high-severity denial of service vulnerability in Red Hat Enterprise Linux 10, published on 31 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Undertow is a flexible performant web server used in JBoss EAP and WildFly. A flaw was found in how Undertow handles WebSocket connections. Specifically, certain configuration limits like message buffer sizes and session timeouts cannot be adjusted and default to being unlimited. This allows a remote attacker to send large amounts of data or maintain connections indefinitely, potentially crashing the server by exhausting its memory or other resources.
Weakness: CWE-770
Which versions are affected by CVE-2026-81624?
How do I fix CVE-2026-81624?
No fix has been published for CVE-2026-81624 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-2026-81624 being exploited?
There is no known exploitation of CVE-2026-81624 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-81624, GHSA-p4f9-3wx9-7g8r, UBUNTU-CVE-2026-81624.