CVE-2026-73937 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/2 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 and unauthorized read access to a subset of Helidon accessible data. CVSS 3.1 Base Score 8.2 (Confidentiality and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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 4.5.0. This security flaw is characterized by its high exploitability and broad accessibility, as it permits unauthenticated attackers to leverage network access via HTTP/2 protocols to compromise the integrity and availability of the application server. The core technical issue stems from improper handling or validation mechanisms within the web server's processing logic when interacting with HTTP/2 traffic streams. This deficiency allows malicious actors to trigger conditions that destabilize the server environment without requiring any form of authentication, thereby bypassing standard access control measures that would typically protect such sensitive infrastructure components.
The operational impact of this vulnerability is severe, primarily manifesting as a complete denial of service through frequent and repeatable crashes or hangs within the Helidon application. This availability impact means that legitimate users are unable to access services hosted on the affected server, leading to significant business disruption. Concurrently, the vulnerability also facilitates unauthorized read access to a subset of data accessible by Helidon itself. While this confidentiality breach is rated as lower severity than the denial-of-service aspect in terms of base score weighting, it still poses a critical risk by allowing attackers to exfiltrate sensitive information stored or processed by the middleware. The combination of these two impacts results in a CVSS 3.1 Base Score of 8.2, indicating a high-severity threat that demands immediate attention from security operations teams responsible for maintaining Oracle Fusion Middleware environments.
From a classification perspective, this vulnerability aligns with Common Weakness Enumeration categories such as CWE-400, which refers to Uncontrolled Resource Consumption leading to denial of service, and potentially CWE-287 if the issue involves improper authentication checks that allow unauthenticated access to sensitive resources. In terms of adversary behavior mapping under the MITRE ATT&CK framework, this vulnerability supports techniques associated with Initial Access via network-based protocols and Impact categories including Service Stop or Data Exfiltration over Application Layer Protocols like HTTP/2. Attackers can utilize automated tools to send malformed or specifically crafted HTTP/2 frames that trigger the resource exhaustion logic or exploit memory handling errors within the server's parser, leading to the observed crashes and data leakage.
Mitigation strategies must focus on immediate remediation through patching and defensive configuration adjustments. The primary recommendation is to apply the latest security patches provided by Oracle for Helidon version 4.5.0 as soon as they are available from official support channels. In scenarios where immediate patching is not feasible, organizations should implement network-level controls such as Web Application Firewalls or rate-limiting rules specifically targeting HTTP/2 traffic patterns associated with known exploit signatures. Additionally, restricting direct external access to the Helidon server by placing it behind a reverse proxy that validates and sanitizes incoming requests can help mitigate exploitation attempts until the underlying code defect is resolved. Continuous monitoring of system logs for signs of repeated connection resets or abnormal resource usage spikes will also aid in detecting potential active exploitation efforts.