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The vulnerability identified as CVE-2026-73894 resides in the Helidon product of Oracle Fusion Middleware, specifically within its Imperative Web Server component. Helidon is a lightweight, open-source microservices framework designed for building cloud-native applications. The affected version is Helidon 4.5.0. This flaw is classified as an improper access control vulnerability, mapped to CWE-284.
The core of the issue lies in insufficient authorization checks performed by the Imperative Web Server when handling incoming HTTP requests. An attacker can exploit this vulnerability remotely without the need for any authentication. By sending specially crafted HTTP requests, the attacker can bypass the server’s access control mechanisms. This allows them to perform unauthorized operations on data that the Helidon application manages. Specifically, the vulnerability grants the attacker the ability to update, insert, or delete data, as well as read data that should be restricted. Furthermore, the attacker can cause a partial denial of service (DoS), disrupting the normal operation of the Helidon service.
The vulnerability is easily exploitable, requiring only network access via HTTP. The CVSS v3.1 base score is 7.3, which is considered High severity. The CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L), indicating a network-accessible attack with low complexity, no required privileges, and no user interaction. This results in a limited but tangible impact on confidentiality, integrity, and availability.
DailyCVE Form:
Platform: Oracle Fusion Middleware
Version: Helidon 4.5.0
Vulnerability: Improper Access Control
Severity: High (7.3 CVSS)
Date: August 18, 2026
Prediction: Expected Patch in October 2026
What Undercode Say:
Check the version of Helidon in use ./helidon --version Query the Oracle Critical Patch Update (CPU) advisory for Helidon fixes Note: The October 2026 CPU advisory is typically released on the third Tuesday of October. Replace the URL with the actual advisory link when it becomes available. curl -s https://www.oracle.com/security-alerts/cpuoct2026.html | grep -i helidon
Exploit: (Educational Purposes!)
- Reconnaissance: An attacker would first identify a target Helidon 4.5.0 service accessible over HTTP.
- Crafting Requests: The attacker would then craft specific HTTP requests designed to exploit the improper access control flaw. These requests would be aimed at API endpoints or data resources that are not properly protected.
- Data Manipulation: By sending these requests, the attacker could perform unauthorized operations such as:
`GET /sensitive-data` to read restricted information.
`POST /api/update` to modify or insert data.
`DELETE /api/resource` to delete data.
- Denial of Service: The attacker could also send a high volume or specific sequence of requests to cause a partial DoS, making the service unstable or unresponsive.
Protection:
The primary mitigation is to upgrade Oracle Helidon to a patched version that addresses CVE-2026-73894. As a temporary measure, administrators should restrict external HTTP traffic to the Helidon service and review and enforce strict access control configurations to ensure all requests are properly authenticated and authorized.
Impact:
Successful exploitation of CVE-2026-73894 can lead to a partial breach of confidentiality, integrity, and availability. An attacker could gain unauthorized read access to sensitive data, leading to data leaks. They could also modify, insert, or delete critical data, compromising data integrity. Furthermore, the ability to cause a partial denial of service can disrupt business operations and affect the availability of the Helidon application. The simplicity of the attack vector (unauthenticated, network access via HTTP) makes this a significant risk.
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Sources:
Reported By: nvd.nist.gov
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