CVE-2026-19204 PUBLISHED

Assigner: eclipse
Reserved: 07.08.2026 Published: 07.09.2026 Updated: 07.09.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Eclipse Foundation
Product	Eclipse Jetty
Versions	Default: unaffected affected from 12.1.0 to 12.1.11 (incl.) affected from 12.0.0 to 12.0.37 (incl.) affected from 11.0.0 to 11.0.31 (incl.) affected from 10.0.0 to 10.0.31 (incl.)

Credits

Arthur Chan reporter
David Korczynski reporter
Adam Korcz reporter

References

https://github.com/jetty/jetty.project/security/advisories/GHSA-85fq-fc5f-7j7g

Problem Types

CWE-770 Allocation of resources without limits or throttling CWE
CWE-789 Memory allocation with excessive size value CWE