CVE-2026-15565 (GCVE-0-2026-15565)

Vulnerability from cvelistv5 – Published: 2026-08-11 08:49 – Updated: 2026-08-12 15:16
VLAI
Title
Undertow: undertow-websockets: undertow: pre-auth dos on websocket endpoint with @serverendpoint class with any @onmessage method
Summary
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-11 17:48 UTC
CWE
  • CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Assigner
References
URL Tags
https://access.redhat.com/errata/RHSA-2026:53806 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-15565 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2490628 issue-trackingx_refsource_REDHAT
Impacted products
Date Public
2026-08-11 05:55
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.