CVE-2026-15565

What it is

A flaw was found in Undertow. A remote attacker can cause Out of Memory on websockets endpoint without authentication on any @ServerEndpoint class that has any @OnMessage method. This allows an attacker to cause Denial of Service attack without authentication and using only a standard WebSocket handshake.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

1.0% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-08-11 09:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-01 01:17 UTC Last updatedMost recent change to the record

Details

Published

2026-08-11 09:17 UTC

Last modified

2026-11-01 01:17 UTC

Exploit probability

1.0% · EPSS, next 30 days

Weakness

CWE-120 · Classic buffer overflow

Record status

Awaiting Analysis

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High