CVE-2026-73900 in Helidon
Summary
by MITRE • 08/19/2026
Vulnerability in the Helidon product of Oracle Fusion Middleware (component: Imperative Web Server). The supported version that is affected is 4.5.1. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP to compromise Helidon. Successful attacks of this vulnerability can result in unauthorized read access to a subset of Helidon accessible data. CVSS 3.1 Base Score 5.3 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).
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Analysis
by VulDB Data Team • 08/19/2026
The identified vulnerability resides within the Imperative Web Server component of Oracle Fusion Middleware Helidon, specifically affecting version 4.5.1. This security flaw is classified as an easily exploitable issue that permits unauthenticated attackers to compromise the integrity and confidentiality of the application server environment. The attack vector requires network access via HTTP, meaning no user interaction or authentication credentials are necessary for exploitation. This characteristic significantly elevates the risk profile, as remote adversaries can initiate attacks from any location with connectivity to the target system without needing prior valid login sessions or social engineering tactics to trick users into triggering the exploit.
The technical nature of this vulnerability centers on an improper access control mechanism within the web server's request handling logic. When processing incoming HTTP requests, the server fails to adequately validate whether the requesting entity possesses sufficient privileges to access specific internal data structures or configuration endpoints. This oversight allows a malicious actor to send crafted HTTP payloads that bypass standard authorization checks. By leveraging this flaw, an attacker can retrieve sensitive information stored within Helidon's accessible memory space or file system, which may include session tokens, application configurations, database connection strings, or other proprietary business logic details. The vulnerability is categorized under CWE-284 Improper Access Control and aligns with the ATT&CK technique T1078 Valid Accounts if any implicit trust mechanisms are abused, though in this unauthenticated context it primarily reflects a failure in enforcing strict boundary checks between public-facing interfaces and internal resources.
The operational impact of successfully exploiting this vulnerability is limited to unauthorized read access for a subset of Helidon accessible data. As indicated by the CVSS 3.1 base score of 5.3, the primary consequence is a loss of confidentiality rather than integrity or availability. The specific vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) confirms that while the attack requires low complexity and no privileges, it does not result in direct system compromise, data modification, or service disruption. However, even limited read access can be devastating if the exposed subset contains sensitive credentials, internal network topology details, or intellectual property. Attackers could use this information as a foothold for further reconnaissance, potentially leading to more severe attacks such as privilege escalation or lateral movement within the enterprise network.
Mitigation strategies must focus on immediate patching and defensive configuration adjustments. The primary remediation is to upgrade Helidon to a version where this access control flaw has been resolved by Oracle Fusion Middleware security updates. In environments where upgrading is not immediately feasible, administrators should implement strict firewall rules or web application firewalls that restrict HTTP traffic to the affected component only from trusted IP ranges. Additionally, enabling comprehensive logging and monitoring for anomalous request patterns targeting internal endpoints can help detect exploitation attempts in real time. It is also critical to ensure that Helidon instances are not exposed directly to untrusted networks without a reverse proxy or gateway layer enforcing additional authentication and authorization checks before requests reach the vulnerable component.