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Oracle Helidon EUVDEUVD-2026-62133

| CVE-2026-73889 MEDIUM
Improper Access Control (CWE-284)
2026-08-18 secalert_us@oracle.com GHSA-g523-9v8v-25c9
5.3
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 4.5.0 service via HTTP
  2. Exploit
    Send unauthenticated crafted HTTP request
  3. Execution
    Trigger auth bypass in Imperative Web Server
  4. Impact
    Read restricted data subset

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 only network access to a Helidon 4.5.0 instance running the Imperative Web Server component over HTTP - no authentication, no special configuration, and no user interaction are required. This is a default-reachable flaw in the specific affected version, constrained solely to version 4.5.0 of the Helidon framework. Exploitation is limited by the fact that only a subset of Helidon-accessible data is exposed (not full system access), and the vulnerability does not affect integrity or availability. Environments where the Helidon HTTP port is not externally reachable (e.g., internal-only microservices behind an API gateway) face significantly reduced practical risk despite the theoretical AV:N classification.

Impact

CVSS 3.1 scores this at 5.3 (Medium), which aligns with the limited scope of impact - partial read access with no integrity or availability consequence. The AV:N/AC:L/PR:N/UI:N vector is concerning from an exploitability standpoint: no authentication, no complexity, no user interaction required. However, the C:L impact cap significantly constrains real-world blast radius, as only a subset of data is exposed rather than full system compromise. No EPSS score was provided in the source data, and the vulnerability is not listed in CISA KEV, suggesting no confirmed active exploitation at the time of disclosure. The 'Authentication Bypass' tag elevates concern above a typical C:L finding, since bypassing auth controls can sometimes be chained with other vulnerabilities. Overall risk is moderate: high exploitability, low direct impact, niche product footprint limits breadth of exposure.

Exploit ScenarioDerived

An unauthenticated attacker with HTTP network access to a Helidon 4.5.0 service sends a crafted request to the Imperative Web Server component, exploiting the authentication bypass to retrieve data that should be restricted to authenticated users. No exploit code is publicly known, but the low attack complexity means exploitation is straightforward once the flaw mechanism is understood. The data obtained is limited to a subset of what the Helidon application can access, making this most useful as a reconnaissance step or for extracting sensitive configuration data exposed through the HTTP layer.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 19, 2026

Unauthorized data exposure in Oracle Helidon 4.5.0's Imperative Web Server component allows unauthenticated remote attackers to read a subset of application-accessible data via HTTP. The vulnerability is tagged as an authentication bypass, meaning protections that should gate read access can be circumvented without credentials. No public exploit code has been identified at time of analysis, and it has not been listed in the CISA KEV catalog, though Oracle disclosed this via their August 2026 Critical Patch Update (CPU).

RemediationAI

Oracle addressed this vulnerability as part of the August 2026 Critical Patch Update. Organizations should apply the patch provided in that CPU by consulting https://www.oracle.com/security-alerts/cspuaug2026.html for the specific remediation artifact applicable to Helidon 4.5.0. No exact patched version number is independently confirmed in the available data beyond the CPU reference. If immediate patching is not feasible, consider restricting network access to Helidon Imperative Web Server endpoints via firewall or API gateway ACLs to trusted IP ranges only, which limits the AV:N exposure but does not eliminate the vulnerability. Disabling unauthenticated HTTP endpoints in the Helidon application configuration, if application function permits, is an additional compensating control. Note that the CPU does not disclose workarounds separate from patching.

Affected VersionsENISA

Helidon 4.5.0

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

Helidon is Oracle's open-source Java microservices framework, offering two programming models: reactive (Helidon SE) and imperative/blocking (Helidon MP, built on MicroProfile). The affected component, the Imperative Web Server, handles synchronous HTTP request processing for Helidon applications. The vulnerability arises in version 4.5.0 specifically within this blocking server path. While no CWE was formally assigned, the 'Authentication Bypass' tag and the CVSS PR:N metric indicate a flaw in the access-control layer of the HTTP handling pipeline - likely a code path that fails to enforce authentication checks before serving certain data. The CVSS vector AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N confirms network reachability, no prerequisites, and a confidentiality-only impact with no integrity or availability consequences.

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Severity by source

Vendor (oracle) PRIMARY 5.3 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
vuln.today AI 5.3 MEDIUM

Network-reachable unauthenticated HTTP bypass with partial confidentiality impact only; no integrity or availability consequence confirmed.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/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
Low
Integrity
None
Availability
None

DescriptionCVE.org

Vulnerability in the Helidon product of Oracle Fusion Middleware (component: Imperative Web Server). The supported version that is affected is 4.5.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP to compromise Helidon. Successful attacks of this vulnerability can result in unauthorized read access to a subset of Helidon accessible data. CVSS 3.1 Base Score 5.3 (Confidentiality impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).

Threat Intelligence Overview

EPSS Score
0.3%
Top 76% exploitable
Prevalence
Low
niche Oracle microservices framework, limited non-Oracle enterprise adoption
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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.3%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

26
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +26
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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