CVE-2026-19204

High

Description

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.

SeverityHigh

CVSS8.7

Exploit probability—

ProductEclipse Jetty

PublishedSep 7, 2026

First seenSep 7, 2026

Weakness typeCWE-770Allocation of resources without limits CWE-789CWE-789

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

Product	Affected versions	Fixed in
Eclipse Foundation Eclipse Jetty	12.1.0 ≤ v ≤ 12.1.11, 12.0.0 ≤ v ≤ 12.0.37, 11.0.0 ≤ v ≤ 11.0.31, 10.0.0 ≤ v ≤ 10.0.31	—

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