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Oracle Helidon EUVDEUVD-2026-62137

| CVE-2026-73893 MEDIUM
Improper Access Control (CWE-284)
2026-08-18 secalert_us@oracle.com GHSA-wx48-r7f4-pjw4
6.5
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 internet-exposed Helidon 4.5.0 endpoint
  2. Delivery
    Send crafted HTTP request to Imperative Web Server
  3. Exploit
    Bypass authentication enforcement
  4. Execution
    Read subset of application data
  5. Impact
    Modify or delete accessible application records

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

Exploitation requires network-level HTTP access to a Helidon 4.5.0 instance running the Imperative Web Server component - no authentication, no user interaction, and no elevated privileges are needed. The CVSS vector AV:N/AC:L/PR:N/UI:N/S:U confirms this is exploitable against default configurations of Helidon 4.5.0 from the network. The primary limiting factors are: (1) the vulnerability is version-specific to 4.5.0 - other Helidon versions are not confirmed affected; (2) impact is scoped to data accessible by the Helidon application, not the broader host system (S:U); and (3) availability is unaffected, so the attack does not cause denial of service. Deployments that are not network-exposed (e.g., internal microservices inaccessible from untrusted networks) face materially lower risk, though the authentication bypass condition itself has no known configuration prerequisite.

Impact

The CVSS 3.1 base score of 6.5 (Medium) reflects real but bounded impact - partial confidentiality and integrity compromise with no availability impact and unchanged scope. The PR:N and AC:L metrics are the most significant signals: the attack requires no credentials and no special conditions, making it suitable for automated exploitation. No EPSS score was provided in the input data, so exploitation probability cannot be quantified precisely. The vulnerability is not listed in CISA KEV, and no public exploit code has been identified, meaning exploitation remains theoretical at time of analysis. However, the 'Authentication Bypass' tag and the zero-privilege, low-complexity profile mean that if a POC emerges, exploitation will be trivial and rapid. Risk priority should be elevated for internet-exposed Helidon 4.5.0 deployments; internal-only deployments face lower immediate risk but should still be patched given Oracle's quarterly CPU cadence.

Exploit ScenarioDerived

An unauthenticated attacker with network access to a Helidon 4.5.0 service sends a specially crafted HTTP request to the Imperative Web Server component that bypasses the authentication enforcement mechanism. The attacker is then able to read a subset of application data or insert, update, or delete records accessible to the Helidon service - without ever presenting valid credentials. No public exploit code has been identified at time of analysis, but the low complexity and zero-privilege requirement mean exploitation would be straightforward once a POC exists.

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

Unauthenticated remote exploitation of Oracle Helidon 4.5.0's Imperative Web Server component allows network-adjacent attackers to bypass authentication and perform unauthorized read and write operations on application data over HTTP. Tagged explicitly as an Authentication Bypass by Oracle's security team, this vulnerability exposes a subset of Helidon-accessible data to disclosure and tampering without requiring credentials or user interaction. No public exploit code has been identified at time of analysis, and the flaw is not listed in CISA KEV, but the low attack complexity and zero-privilege requirement make it a straightforward target for automated scanning.

RemediationAI

Consult the Oracle Critical Security Patch Update advisory for August 2026 at https://www.oracle.com/security-alerts/cspuaug2026.html for the vendor-released fix version; an exact patched release number is not independently confirmed in the available data, so defer to the official CPU documentation. As a compensating control while patching, restrict network access to Helidon Imperative Web Server endpoints at the firewall or load-balancer layer, permitting only trusted internal networks or authenticated upstream proxies to reach the service. If the deployment architecture permits, place the Helidon service behind an API gateway or reverse proxy that enforces authentication independently, which would break the unauthenticated exploitation path. Note that relying solely on perimeter controls is a temporary measure - the authentication bypass exists within the application layer and must be addressed by applying the vendor patch.

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, part of the Oracle Fusion Middleware product family. The Imperative Web Server is the reactive-imperative hybrid HTTP server component within Helidon, handling inbound HTTP request routing and middleware pipeline execution. The vulnerability resides in this component at version 4.5.0. No CWE identifier has been assigned, but the 'Authentication Bypass' tag strongly indicates a flaw in the authentication enforcement layer of the HTTP server - likely a missing or bypassable authentication check in a specific request path or handler, rather than a cryptographic weakness. The CVSS vector (AV:N/AC:L/PR:N/UI:N) confirms the flaw is reachable over the network without prior authentication, consistent with an authentication gate that can be circumvented via crafted HTTP requests.

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Severity by source

Vendor (oracle) PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
vuln.today AI 6.5 MEDIUM

Network-reachable authentication bypass with no prerequisites; partial data read and write impact only, no availability loss and no scope change.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/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
Low
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 update, insert or delete access to some of Helidon accessible data as well as unauthorized read access to a subset of Helidon accessible data. CVSS 3.1 Base Score 6.5 (Confidentiality and Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N).

Threat Intelligence Overview

EPSS Score
0.3%
Top 81% exploitable
Prevalence
Low
niche Oracle microservices framework, limited to Oracle ecosystem adopters
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

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
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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