CVE-2026-73891 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 update, insert or delete access to some of Helidon accessible data as well as unauthorized read access to a subset of Helidon accessible data and unauthorized ability to cause a partial denial of service (partial DOS) of Helidon. CVSS 3.1 Base Score 7.3 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L).
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Analysis
by VulDB Data Team • 08/19/2026
The vulnerability identified in Oracle Fusion Middleware Helidon version 4.5.0 represents a critical security flaw within the Imperative Web Server component, which serves as the core runtime for building reactive microservices and web applications. This specific weakness allows an unauthenticated attacker to exploit the system over standard HTTP network connections without requiring any prior authentication or user interaction. The presence of this vulnerability indicates a fundamental failure in input validation or access control mechanisms within the server's request handling logic, enabling malicious actors to interact directly with internal data structures that should be protected from external manipulation.
From a technical perspective, the flaw facilitates unauthorized modifications to accessible data through update, insert, and delete operations, as well as unauthorized read access to sensitive information subsets. This behavior is characteristic of an Insecure Direct Object Reference or improper authorization check where the server fails to verify if the requesting entity has sufficient privileges for the specific resource being accessed. The ability to perform write operations suggests that input sanitization is insufficient, potentially allowing attackers to inject malicious payloads or alter database states directly through crafted HTTP requests. This aligns with CWE-862 Missing Authorization and CWE-917 Improper Control of Modification of Dynamic Variables, highlighting a severe lapse in enforcing the principle of least privilege for API endpoints exposed by the Helidon server.
The operational impact of this vulnerability is significant due to its high severity score of 7.3 on the CVSS v3.1 scale, reflecting substantial risks across confidentiality, integrity, and availability dimensions. The unauthorized read access compromises data confidentiality, potentially exposing proprietary business logic or user information stored within the Helidon-managed services. Simultaneously, the ability to update, insert, or delete records undermines system integrity, allowing attackers to corrupt datasets, introduce backdoors, or disrupt application functionality by altering critical configuration states. Furthermore, the vulnerability enables a partial denial of service condition, meaning that an attacker can degrade performance or render specific features unavailable by exhausting server resources through malicious requests, thereby impacting business continuity and user experience.
In terms of threat modeling, this attack vector corresponds to ATT&CK technique T1078 Valid Accounts if authentication were bypassed via other means, but more accurately maps to T1190 Exploit Public-Facing Application given the unauthenticated nature over HTTP. The lack of required interaction (UI:N) and low complexity (AC:L) makes this vulnerability highly attractive for automated exploitation by threat actors scanning public-facing infrastructure. Organizations relying on Helidon 4.5.0 are at immediate risk if these endpoints are exposed to internal or external networks without additional protective layers such as Web Application Firewalls that can detect anomalous request patterns indicative of data manipulation attempts.
Mitigation strategies must prioritize upgrading the Oracle Fusion Middleware Helidon component to a patched version where the vendor has addressed the underlying authorization and input validation flaws. Until an upgrade is feasible, network-level controls should be implemented to restrict access to affected endpoints strictly to trusted IP ranges or internal subnets. Implementing strict rate limiting can help mitigate the partial denial of service aspect by preventing resource exhaustion attacks. Additionally, deploying a Web Application Firewall with rulesets designed to detect SQL injection patterns and unauthorized HTTP method usage can provide an additional layer of defense against exploitation attempts targeting this specific vulnerability in the Imperative Web Server component.