CVE-2026-73889 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 4.5.0. 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 • 08/19/2026
The identified vulnerability resides within the Imperative Web Server component of Oracle Fusion Middleware Helidon, specifically affecting version 4.5.0. This security flaw represents a significant risk to organizations relying on this framework for building microservices and cloud-native applications in Java environments. The core issue stems from an improper access control mechanism that fails to adequately restrict unauthenticated requests targeting specific internal endpoints or data structures exposed by the web server. As a result, any actor with network connectivity to the affected service can interact with these unprotected areas without needing valid credentials or authentication tokens. This lack of enforcement allows external parties to bypass standard security boundaries and gain visibility into sensitive information that should remain restricted to authorized users only.
From a technical perspective, this vulnerability is classified under CWE-284, which denotes Improper Access Control, specifically highlighting the failure to enforce restrictions on authenticated users or unauthenticated actors accessing resources. The attack vector is network-based with low complexity, meaning no special conditions are required for exploitation beyond having HTTP access to the target system. Furthermore, it requires no user interaction and carries no prerequisites regarding privileges, making it highly accessible to automated scanning tools and opportunistic attackers alike. The impact of this flaw is primarily confined to confidentiality, as indicated by a CVSS 3.1 base score of 5.3 with a vector string of AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. This scoring reflects that while the integrity and availability of the system remain unaffected, there is a measurable loss of confidentiality where an attacker can read a subset of accessible data within Helidon.
The operational impact of this vulnerability extends beyond simple data leakage. In enterprise environments using Oracle Fusion Middleware, such exposure could lead to the disclosure of internal configuration details, session identifiers, or other metadata that aids in further reconnaissance and subsequent attacks. Attackers may use this information to map out the application architecture, identify additional entry points, or craft more sophisticated exploits targeting authenticated components. This aligns with MITRE ATT&CK technique T1078, Valid Accounts, although in this case, it involves exploiting a lack of authentication rather than stealing valid credentials initially. The ability to read internal data can also facilitate social engineering attacks if sensitive operational information is exposed, thereby increasing the overall risk profile for the organization hosting these services.
To mitigate this vulnerability, immediate action should be taken by Oracle users to apply available patches or updates that address the access control flaws in Helidon version 4.5.0. Organizations must verify their deployment configurations and ensure that all instances of the affected component are updated to a secure version where proper authentication checks have been implemented for previously unprotected endpoints. Additionally, implementing network-level security controls such as firewalls can help restrict direct HTTP access from untrusted networks to these services until patches are applied. Regular vulnerability scanning and penetration testing should be conducted to identify similar misconfigurations in other parts of the application stack. Monitoring logs for unusual patterns of unauthenticated requests targeting internal endpoints will also aid in detecting potential exploitation attempts in real-time, allowing security teams to respond promptly to any signs of compromise.