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Oracle Helidon EUVDEUVD-2026-62147

| CVE-2026-73903 HIGH
Improper Access Control (CWE-284)
2026-08-18 secalert_us@oracle.com GHSA-9pr8-f4gj-9hr5
7.5
CVSS 3.1 · Vendor: oracle
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Identify Helidon 4.5.1 HTTP service on network
  2. Delivery
    Send crafted unauthenticated HTTP request
  3. Exploit
    Bypass Imperative Web Server authentication gate
  4. Execution
    Gain unauthorized write access
  5. Impact
    Create, modify, or delete critical application data

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Access control enforcement
MITRE ATT&CK

1 technique across 1 tactic: Defense Evasion

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

The vulnerability requires network-level HTTP access to a system running Oracle Helidon exactly version 4.5.1 with the Imperative Web Server component active. The CVSS vector (AV:N/AC:L/PR:N/UI:N) confirms that no authentication, no elevated privileges, no special configuration, and no user interaction are required - exploitation is viable against any default deployment of the affected version reachable over the network. Exploitation is bounded to version 4.5.1 specifically per Oracle's advisory; no other versions are confirmed affected. The impact is strictly integrity-scoped (I:H, C:N, A:N), meaning the attacker can manipulate data but cannot read confidential content or cause denial of service through this vulnerability alone. Environments where Helidon 4.5.1 services are isolated behind internal network boundaries or where HTTP access is restricted to authenticated proxies face significantly reduced practical risk.

Impact

The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N) and Oracle's 'easily exploitable' classification together paint a clear high-priority picture for any environment running Helidon 4.5.1 exposed to untrusted networks: no authentication, no complexity barrier, no user interaction required. The integrity-only impact (I:H with C:N and A:N) means the attacker cannot read sensitive data or crash the service, which meaningfully constrains the blast radius relative to a full-compromise scenario. No EPSS score was provided in the intelligence data, so exploitation probability cannot be quantified independently. The vulnerability is not listed in the CISA KEV catalog, indicating no confirmed active exploitation at time of analysis, and no public proof-of-concept has been identified. The net assessment is that this is a genuine remediation priority for Helidon 4.5.1 deployments - particularly services with internet-facing HTTP endpoints or those protecting mutable data stores - but the absence of KEV listing and POC code moderates urgency compared to actively exploited flaws of similar CVSS weight.

Exploit ScenarioDerived

An unauthenticated remote attacker identifies a Helidon 4.5.1 service with the Imperative Web Server component exposed over HTTP and sends a specially crafted request that bypasses the server's authentication controls. Without any credentials, the attacker gains write-equivalent access to data the Helidon service can reach, enabling bulk modification, deletion, or injection of records - for example, corrupting application state or poisoning a backend data store. No public proof-of-concept code has been identified, but Oracle's 'easily exploitable' classification and the low-complexity CVSS vector suggest the authentication bypass does not require sophisticated tooling to trigger.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 18, 2026

Authentication bypass in Oracle Helidon 4.5.1 (Imperative Web Server component) exposes applications to unauthenticated remote attackers who can create, modify, or delete critical data accessible to the service via standard HTTP requests. Oracle classifies this as 'easily exploitable' with a CVSS 3.1 score of 7.5, reflecting a network-accessible, zero-complexity attack requiring no credentials or user interaction. No public exploit code or CISA KEV listing has been identified at time of analysis; Oracle addressed the issue in the August 2026 Critical Patch Update.

RemediationAI

Apply the patch released by Oracle in the August 2026 Critical Patch Update, documented at https://www.oracle.com/security-alerts/cspuaug2026.html. The advisory provides specific component-level patch instructions; consult it for the exact patched build of Helidon to upgrade to, as an exact fix version was not independently extractable from the available intelligence data (patch available per vendor advisory). If immediate patching is not possible, restrict network access to the Helidon HTTP service at the infrastructure layer - firewall rules, API gateway ACLs, or load balancer policies should limit inbound HTTP traffic to trusted IP ranges or internal networks only; this reduces attack surface but does not eliminate the underlying flaw and introduces operational complexity for legitimate clients. If the Imperative Web Server component is not required by the application, disabling or avoiding it in favor of Helidon's reactive SE or MP programming models is a structural mitigation, though this carries significant application refactoring trade-offs and may not be feasible without extended development effort.

Affected VersionsENISA

Helidon 4.5.1

Affected Packages

euvd helidon no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Oracle Helidon is an open-source Java microservices framework offered under the Oracle Fusion Middleware umbrella, featuring two programming models: a reactive/functional SE model and a MicroProfile-aligned MP model. Helidon 4.x introduced an 'Imperative Web Server' API within the SE model, providing a traditional imperative-style HTTP server programming interface suited for synchronous request handling. The affected component (Imperative Web Server in version 4.5.1) contains an authentication bypass weakness - the advisory tag identifies this as an Authentication Bypass class flaw. No CWE identifier was assigned in the available data, but the root cause class is consistent with CWE-287 (Improper Authentication) or CWE-306 (Missing Authentication for Critical Function), where authentication enforcement is absent or bypassable at the HTTP request handling layer. The vulnerability is reached entirely over the network via HTTP, implicating the server's request routing or middleware authentication pipeline.

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Severity by source

Vendor (oracle) PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
vuln.today AI 7.5 HIGH

Network-reachable HTTP authentication bypass requires no credentials (PR:N) and no complexity (AC:L); impact is integrity-only with no confidentiality or availability consequence confirmed.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (oracle).

CVSS VectorVendor: oracle

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

DescriptionCVE.org

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 creation, deletion or modification access to critical data or all Helidon accessible data. CVSS 3.1 Base Score 7.5 (Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).

Executive ViewAI

Why It Matters

Oracle Helidon 4.5.1 contains an authentication bypass vulnerability (CVSS 7.5); while no public exploit has been identified at time of analysis, unauthenticated remote attackers can create, modify, or delete critical application data without credentials. Organizations using this component face immediate risk of data manipulation and potential compliance violations from trivially exploitable, network-accessible attacks.

Business Impact: High
Compensating Controls

Apply vendor patch: Oracle August 2026 Critical Patch Update.

Threat Intelligence Overview

EPSS Score
0.3%
Top 73% exploitable
Prevalence
Low
niche Oracle Java microservices framework, limited enterprise footprint
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.3%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
High
Technical Impact
Partial

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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