CVE-2026-73936 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 ability to cause a hang or frequently repeatable crash (complete DOS) of Helidon. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
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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 a high-severity issue with a CVSS v3.1 base score of 7.5, indicating significant risk to system availability. The attack vector for this vulnerability is network-based and accessible via HTTP, allowing an unauthenticated attacker to exploit the weakness without requiring any prior credentials or user interaction. This lack of authentication requirements makes the vulnerability particularly dangerous in production environments where services are exposed to public networks or internal subnets with broad access policies.
The technical nature of this flaw centers on a mechanism that permits remote attackers to trigger conditions leading to service unavailability. Specifically, successful exploitation results in either a hang or a frequently repeatable crash of the Helidon server process. This behavior constitutes a classic Denial of Service (DoS) attack scenario where the integrity and availability of the application are compromised. The repetitive nature of the crash suggests that an attacker can sustainably disrupt service by repeatedly sending crafted requests, thereby preventing legitimate users from accessing the hosted applications or APIs.
From a classification perspective, this vulnerability aligns with CWE-400, which describes uncontrolled resource consumption leading to denial of service conditions. In terms of offensive security frameworks such as MITRE ATT&CK, this activity falls under T1499: Endpoint Denial of Service, specifically utilizing application layer exhaustion techniques. The exploitation does not involve data exfiltration or unauthorized modification of system state, which explains the zero impact on Confidentiality and Integrity in the CVSS vector, but the complete loss of Availability is sufficient to warrant a high severity rating due to the operational disruption it causes.
The operational impact of this vulnerability extends beyond simple downtime; it can lead to cascading failures if Helidon serves as an API gateway or load balancer for downstream services. The inability to serve requests may trigger timeout mechanisms in client applications, leading to increased latency and potential data loss in transactional systems that rely on synchronous communication with the affected middleware. Furthermore, frequent crashes necessitate manual intervention by system administrators to restart services, increasing operational overhead and reducing overall system reliability.
Mitigation strategies should prioritize immediate patching of the Helidon component to version 4.5.1 or later if a fixed release is available from Oracle. In cases where patching is not immediately feasible, network-level controls such as Web Application Firewalls (WAFs) can be configured to detect and block anomalous HTTP request patterns associated with this DoS vector rate limiting should also be implemented at the infrastructure level to mitigate the impact of repeated requests. Additionally, reviewing access control policies to restrict direct exposure of Helidon endpoints to untrusted networks reduces the attack surface available to potential adversaries until a permanent fix is deployed.