CVE-2026-91409

Received Received - Intake

Denial of Service in Oracle Java SE

Publication date: 2026-10-20

Last updated on: 2026-10-20

Assigner: Oracle

Description

Vulnerability in Oracle Java SE (component: Networking). The supported version that is affected is Oracle Java SE: 27. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE. Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Java SE. Note: This vulnerability can be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. This vulnerability also applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. CVSS 3.1 Base Score 3.7 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L).

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-20

Last Modified

2026-10-20

Generated

2026-10-21

AI Q&A

2026-10-21

EPSS Evaluated

N/A

NVD

CVE-2026-91409

Affected Vendors & Products

Vendor	Product	Version / Range
Oracle	Corporation	Oracle Java SE 27

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a vulnerability in Oracle Java SE version 27. It allows an unauthenticated attacker with network access to cause a partial denial of service (DOS) in the affected Java SE component. The attack is difficult to exploit and requires access via multiple protocols.

Detection Guidance

Detection involves checking for affected Oracle Java SE versions (27) and monitoring for partial denial of service conditions. Inspect Java applications using network protocols and APIs. Check logs for unusual network activity or crashes in Java processes.

Impact Analysis

If exploited, this vulnerability could lead to a partial denial of service in Oracle Java SE, disrupting its availability. Systems relying on Java SE for critical functions may experience reduced performance or downtime.

Mitigation Strategies

Apply the latest Oracle Java SE patches immediately. Disable unnecessary Java network services or APIs. Restrict network access to Java applications. Monitor for partial denial of service attempts and update Java deployments in sandboxed environments.

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