CVE-2026-83280 in Helidon
Summary
by MITRE • 09/16/2026
Vulnerability in the Helidon product of Oracle Fusion Middleware (component: helidon-webserver-http2). Supported versions that are affected are 4.0.0-4.5.4. 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. 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 • 09/16/2026
The identified vulnerability resides within the helidon-webserver-http2 component of Oracle Fusion Middleware, specifically affecting Helidon versions ranging from 4.0.0 through 4.5.4. This security flaw is classified as a high-severity availability issue with a CVSS v3.1 base score of 7.5. The vector indicates that the attack requires no authentication and can be executed remotely over the network via HTTP/2, leveraging low complexity to achieve complete denial of service conditions such as hangs or frequent crashes. This represents a significant risk for organizations relying on Helidon for high-availability web services, as it allows an unauthenticated external actor to disrupt service continuity without needing valid credentials or user interaction.
From a technical perspective, the vulnerability stems from improper handling of HTTP/2 protocol frames within the server implementation. While specific internal mechanics may vary based on patch versions, such flaws typically involve race conditions, buffer overflows, or logic errors triggered by malformed or specifically crafted HTTP/2 requests. When an attacker sends these malicious packets, they exploit weaknesses in how the webserver processes stream states or header compression tables. The result is a state corruption that forces the server process to terminate unexpectedly or enter an unrecoverable hung state. This aligns with CWE-400, which describes uncontrolled resource consumption leading to denial of service, and potentially CWE-20 if it involves improper input validation of protocol-specific data structures.
The operational impact of this vulnerability is severe due to its direct effect on system availability. A successful exploitation results in the complete cessation of Helidon services for affected instances. Since HTTP/2 is widely adopted for modern web applications requiring multiplexing and header compression, attackers can easily target these endpoints using standard networking tools or custom scripts designed to trigger the specific flaw. The lack of authentication requirements means that any entity with network reachability to the vulnerable server port can execute this attack. This creates a persistent threat vector where automated bots could continuously probe for the vulnerability, causing intermittent outages that degrade user experience and potentially violate service level agreements regarding uptime guarantees.
Mitigation strategies must prioritize immediate patching as the primary defense mechanism. Organizations running Helidon versions 4.0.0 to 4.5.4 should upgrade to a patched version released by Oracle after the disclosure of this vulnerability. In environments where upgrading is not immediately feasible, network-level controls can provide temporary relief. Implementing Web Application Firewalls with specific rulesets capable of detecting and blocking anomalous HTTP/2 traffic patterns may help mitigate exploitation attempts. Additionally, rate limiting on incoming connections to Helidon endpoints can reduce the effectiveness of automated denial-of-service attacks by throttling the volume of requests from single sources. Regular security audits and penetration testing focused on protocol compliance are also recommended to identify similar implementation weaknesses in other components of the middleware stack.
This vulnerability maps directly to MITRE ATT&CK technique T1499, Endpoint Denial of Service, specifically under the sub-technique for resource exhaustion via application layer attacks. It also relates to CWE-787, out-of-bounds write, if memory corruption is involved in the crash mechanism, or CWE-611, improper XML external entity reference, if parsing errors are the root cause, though HTTP/2 frame handling issues often fall under generic protocol implementation flaws categorized as CWE-94. Security teams should monitor for indicators of compromise such as sudden spikes in connection resets or abnormal CPU usage patterns associated with Helidon processes, which may signal ongoing exploitation attempts against this unpatched vulnerability.