CVE-2026-19204
Published:September 07, 2026
Updated:September 22, 2026
A client may send a WebSocket frame with an unknown opcode and a very large declared payload length, causing Jetty to attempt a large memory allocation and potentially exhaust the JVM heap.
This occurs when auto-fragmentation is enabled, as unknown opcodes bypass the normal maximum frame size handling and payload allocation occurs before the opcode is validated.
Affected Packages
org.eclipse.jetty.websocket:jetty-websocket-core-common (JAVA):
Affected version(s) >=12.0.0 <12.0.38Fix Suggestion:
Update to version 12.0.38org.eclipse.jetty.websocket:jetty-websocket-core-common (JAVA):
Affected version(s) >=12.1.0 <12.1.12Fix Suggestion:
Update to version 12.1.12Related Resources (3)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
0.29