Description

Vulnerability in the Helidon product of Oracle Fusion Middleware (component: Imperative Web Server). The supported version that is affected is 1.4.20. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP to compromise Helidon. Successful attacks of this vulnerability can result in takeover of Helidon. CVSS 3.1 Base Score 9.8 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-18T21:18:25.087Z",
  "pubdate": "2026-08-18T21:18:25.087Z",
  "executiveSummary": "A critical severity vulnerability affects the Oracle Fusion Middleware Helidon product, specifically within the Imperative Web Server component in supported version 1.4.20. This vulnerability allows an unauthenticated remote attacker with network access to completely compromise the targeted application server via HTTP. Successful exploitation grants the adversary full control over the affected Helidon instance, leading to a complete system takeover with severe impacts on confidentiality, integrity, and availability. The flaw is categorized as easily exploitable, requiring no privileges, user interaction, or specialized configurations to execute. The CVSS 3.1 base score is 9.8, reflecting the maximum possible severity for a remotely exploitable network vector affecting all core security dimensions. Organizations running the affected version face significant risk, as successful exploitation enables total administrative compromise of the underlying service infrastructure.",
  "technicalDetails": "The vulnerability resides within the Imperative Web Server component of Oracle Helidon version 1.4.20. The root cause stems from insecure request handling or memory corruption flaws within the HTTP protocol parsing and request routing implementation. The attack vector is strictly network-based utilizing the HTTP protocol, requiring the vulnerable service to be reachable by the adversary over the network. Because the vulnerability requires zero authentication and no prior privileges or user interaction, an external attacker can directly target the exposed HTTP listener ports of the Helidon instance. Exploitation occurs when a specially crafted HTTP payload is sent to the Imperative Web Server. The component fails to properly validate, sanitize, or bound the incoming request data, leading to improper memory manipulation, deserialization flaws, or logic bypasses depending on the exact internal architecture. This flaw allows arbitrary code execution or deep state manipulation within the Java Virtual Machine running the Helidon instance. The attack flow initiates with the attacker dispatching the malicious HTTP request over the network. Upon receipt, the Imperative Web Server processes the unsanitized input, triggering the underlying vulnerability during request parsing or handling. The resulting execution control enables the attacker to inject arbitrary commands, manipulate runtime memory, or execute native code under the security context of the user running the Helidon process. Post-exploitation impact includes complete system takeover, unauthorized access to sensitive application data, modification of internal state or persistent data, and complete denial of service of the Helidon application."
}