CVE-2026-73899 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 3.2.19. 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 3.2.19. This security flaw represents a significant risk to organizations relying on this framework for building reactive microservices and web applications in Java environments. The core issue stems from an improper access control mechanism that fails to adequately restrict data exposure based on user authentication status or role-based permissions. As a result, the application logic inadvertently exposes sensitive internal states or configuration details to any entity capable of establishing network connectivity via standard HTTP protocols. This architectural weakness allows external actors to bypass intended security boundaries without requiring valid credentials or complex exploitation techniques, highlighting a fundamental gap in how session data and server-side resources are managed within the imperative request handling pipeline.
From an operational perspective, this vulnerability enables unauthenticated attackers with network access to achieve unauthorized read access to a subset of Helidon accessible data. The impact is primarily confined to confidentiality, as indicated by the CVSS 3.1 base score of 5.3 and the vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N). While there are no immediate implications for integrity or availability in this specific instance, the leakage of internal data can serve as a critical reconnaissance step for further attacks. Attackers may extract sensitive information such as session tokens, internal API endpoints, configuration parameters, or user-specific metadata that was not intended to be publicly accessible. This exposure facilitates subsequent phases of an attack chain, including privilege escalation, social engineering, or targeted exploitation of other system components once the attacker has a clearer understanding of the environment's structure and data sensitivity levels.
In terms of industry standard classifications, this vulnerability aligns with CWE-200: Information Exposure, where security-relevant information is disclosed to an unauthorized actor without explicit intent. It also relates closely to CWE-862: Missing Authorization, as the server fails to enforce proper access controls on specific resources or endpoints. Furthermore, within the MITRE ATT&CK framework, this behavior corresponds to T1005: Data from Local System, where adversaries seek to collect data stored locally on a compromised system for later exfiltration. The low complexity and lack of required user interaction make it particularly dangerous in public-facing deployments where HTTP traffic is routinely monitored by potential threat actors scanning for vulnerable services.
To mitigate this risk, immediate action should be taken to upgrade the Helidon framework to a patched version that addresses these access control deficiencies. Oracle has likely released updates or patches specifically targeting the Imperative Web Server component to enforce stricter validation and authorization checks before data serialization occurs. Organizations must also implement defense-in-depth strategies by placing reverse proxies such as NGINX, Apache HTTP Server, or cloud-based load balancers in front of Helidon instances. These intermediaries can be configured with additional security headers, rate limiting, and IP whitelisting to restrict access to sensitive endpoints even if the underlying application remains vulnerable during transition periods. Regular vulnerability scanning and penetration testing should be conducted to identify similar misconfigurations across other services within the Fusion Middleware ecosystem, ensuring that all exposed interfaces adhere to the principle of least privilege and do not leak internal state information over unauthenticated HTTP channels.