CVE-2026-19204
Description
A flaw was found in Jetty. A remote attacker can exploit this vulnerability by sending a specially crafted WebSocket frame with an unknown operation code (opcode) and a very large declared payload length. When auto-fragmentation is enabled, these unknown opcodes bypass the normal maximum frame size handling, leading Jetty to attempt a large memory allocation before validating the opcode. This can cause the Java Virtual Machine (JVM) heap to be exhausted, resulting in a Denial of Service (DoS) for the affected system.
Statement
Jetty in affected Red Hat products can allow a remote attacker to exhaust the JVM heap by sending a crafted WebSocket frame with a reserved opcode and a large declared payload length to a reachable WebSocket endpoint. Auto-fragmentation is enabled by default, allowing allocation before the invalid opcode is rejected. Remediation is being pursued for affected shipped versions.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Memory)
Not controlling memory allocation can result in a request for too much system memory, possibly leading to a crash of the application due to out-of-memory conditions, or the consumption of a large amount of memory on the system.
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