CVE-2026-19204

published 2026-09-07

CVE-2026-19204: 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…

Priority P3 47 high 8.7 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 E X CR X IR X AR X MAV X MAC X MAT X MPR X MUI X MVC X MVI X MVA X MSC X MSI X MSA X S X AU X R X V X RE X U X

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

4 ranges

Vendor	Product	Version range	Fixed in
eclipse_foundation	eclipse_jetty	10.0.0 – 10.0.31	—
eclipse_foundation	eclipse_jetty	11.0.0 – 11.0.31	—
eclipse_foundation	eclipse_jetty	12.0.0 – 12.0.37	—
eclipse_foundation	eclipse_jetty	12.1.0 – 12.1.11	—

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.

CWE-770 CWE-789