CVE-2026-101586 in Helidon
Summary
by MITRE • 10/21/2026
Vulnerability in the Helidon product of Oracle Fusion Middleware (component: helidon-webclient). Supported versions that are affected are 4.0.0-4.5.5 and 27.0.0. 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 • 10/22/2026
The identified vulnerability resides within the helidon-webclient component of Oracle Fusion Middleware's Helidon product line, specifically affecting versions ranging from 4.0.0 through 4.5.5 and version 27.0.0. This security flaw represents a significant risk to organizations relying on these specific releases for their microservices architecture needs. The core issue stems from an improper access control mechanism within the web client implementation, which fails to adequately restrict data retrieval operations based on user authentication status or session validity. As a result, the component exposes sensitive internal states and configuration details that are intended to be protected by standard security boundaries.
From a technical perspective, this vulnerability is classified as CWE-284, Improper Access Control, specifically manifesting in scenarios where authorization checks are bypassed due to flawed logic within the HTTP request handling pipeline. The flaw allows an unauthenticated attacker who has network access via HTTP to exploit the misconfiguration without requiring any user interaction or complex exploitation techniques. This aligns with ATT&CK technique T1078, Valid Accounts, although in this case, it is exploited by attackers operating entirely outside of authenticated sessions, effectively treating public endpoints as if they were restricted resources. The simplicity of the attack vector means that automated scanning tools can easily detect and exploit this weakness across large networks.
The operational impact of this vulnerability centers on a breach of confidentiality rather than integrity or availability. Successful exploitation enables unauthorized read access to a subset of Helidon accessible data, which may include internal service discovery information, configuration parameters, or cached response payloads depending on the specific deployment context. While the CVSS 3.1 base score is rated at 5.3 indicating medium severity, the actual business impact can vary significantly based on what data is exposed within those subsets. For instance, exposure of internal API endpoints could facilitate further reconnaissance and subsequent attacks against other services in a microservices mesh. The vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) confirms that the attack is network-based, requires low complexity, demands no privileges or user interaction, and results only in limited confidentiality loss without affecting system integrity or availability directly.
To mitigate this risk, organizations running affected versions of Oracle Fusion Middleware must prioritize immediate patching to a version where the access control logic has been corrected by Oracle engineering teams. In environments where upgrading is not immediately feasible, network-level controls such as Web Application Firewalls should be configured to block unauthorized requests targeting known vulnerable endpoints associated with the helidon-webclient component. Additionally, implementing strict input validation and ensuring that all internal APIs enforce authentication checks at the gateway level can provide a layer of defense in depth against this specific class of access control bypasses. Regular security audits focusing on HTTP request handling logic are recommended to identify similar patterns across other components within the middleware stack.