High severity · published Aug 11, 2026
CVE-2026-15565
Undertow: undertow-websockets: undertow: pre-auth dos on websocket endpoint with @serverendpoint class with any @onmessage method
7.5
CVSS
1.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.2% · higher than 67% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Data Grid 8 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Fuse 7 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat JBoss Enterprise Application Platform 7 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 8 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 9 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 10 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat JBoss Enterprise Application Platform 8.1.8.GA · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Single Sign-On 7 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat build of Apache Camel for Spring Boot 4 · Red Hat
All versions, or not specified · source: vendor
Affected product
RH
Red Hat build of Apache Camel for Spring Boot 4
Red Hat
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-15565
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-15565
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:53644
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:53645
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:53646
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:53806
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:70228
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:70229
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