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Oracle Helidon EUVDEUVD-2026-62146

| CVE-2026-73902 HIGH
Improper Access Control (CWE-284)
2026-08-18 secalert_us@oracle.com GHSA-2656-hqjx-j857
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 exposed Helidon 3.2.19 HTTP endpoint
  2. Delivery
    Craft malicious HTTP request
  3. Exploit
    Send request to Imperative Web Server
  4. Execution
    Trigger hang or crash in request handler
  5. Impact
    Service becomes unavailable

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

No special configuration or non-default settings are required - the vulnerability exists in the default operational mode of the Helidon 3.2.19 Imperative Web Server when accessible over HTTP from the network. The CVSS vector AV:N/AC:L/PR:N/UI:N confirms exploitation requires only network connectivity to the HTTP port; no authentication, no user interaction, and no special deployment configuration is needed. Exploitation is limited to Helidon version 3.2.19 specifically (other versions not confirmed affected), and only the Imperative Web Server component is implicated - deployments using only Helidon's reactive/non-blocking server model may not be affected, though this distinction is not confirmed by the advisory.

Impact

The CVSS 7.5 High score accurately reflects the straightforward exploitability: network-reachable, no authentication, no user interaction, low complexity. The impact is scoped entirely to availability - there is no confidentiality or integrity component - which limits the blast radius to service disruption rather than data compromise. No EPSS score was provided in the input data, so exploitation probability cannot be quantified. The vulnerability is not listed in the CISA KEV catalog and no public proof-of-concept has been identified, reducing immediate threat urgency relative to actively exploited issues. Helidon has a relatively limited deployment footprint compared to mainstream Java frameworks, which further constrains real-world exposure; however, any team running Helidon 3.2.19 as an internet-facing or intranet microservice endpoint - even a mid-sized municipal IT team in boleslawiec managing internal services - should treat this as urgent given the zero-barrier exploitation path. The primary concern is targeted disruption of microservice infrastructure rather than opportunistic mass exploitation.

Exploit ScenarioDerived

An unauthenticated remote attacker identifies a Helidon 3.2.19 Imperative Web Server endpoint accessible over HTTP and sends a specially crafted HTTP request designed to trigger a hang or crash in the request-processing logic. The server becomes unresponsive or terminates, causing a complete denial of service for all users of that microservice. No public exploit code has been identified at time of analysis, but the low attack complexity (AC:L) suggests the trigger condition is not difficult to reproduce once discovered.

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

Unauthenticated remote denial-of-service in Oracle Helidon 3.2.19 allows a network attacker to hang or crash the Imperative Web Server component via crafted HTTP requests, causing complete loss of service availability. The vulnerability requires no privileges, no user interaction, and is reachable over standard HTTP, making it trivially exploitable against any exposed Helidon 3.2.19 instance. No public exploit code has been identified at time of analysis, and the flaw is not listed in the CISA KEV catalog.

RemediationAI

Consult the Oracle August 2026 Critical Patch Update advisory at https://www.oracle.com/security-alerts/cspuaug2026.html for the specific patched version and apply the recommended Oracle patch. The advisory does not disclose an exact fixed version number in the available data, so the precise upgrade target should be confirmed directly from the Oracle CPU documentation before upgrading. As a compensating control where immediate patching is not possible, restrict network access to Helidon's HTTP port using firewall rules or API gateway policies to limit exposure to trusted source IPs only, accepting the trade-off that this reduces exploitability but does not eliminate the underlying flaw. Additionally, deploying a rate-limiting reverse proxy or load balancer in front of Helidon instances can reduce the impact of repeated crash attempts by absorbing or throttling malformed requests, though this does not prevent a single well-crafted request from triggering the hang condition if one exists.

Affected VersionsENISA

Helidon 3.2.19

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 a Java-based microservices framework developed by Oracle, part of the Fusion Middleware portfolio. The affected component is the Imperative Web Server, which is Helidon's synchronous, blocking HTTP server model (as distinct from the reactive/non-blocking model). The vulnerability affects specifically version 3.2.19 per Oracle's August 2026 Critical Patch Update advisory. No CWE identifier has been assigned, so the precise root cause class - whether resource exhaustion, infinite loop, unhandled exception, or similar - cannot be confirmed from available data. The CVSS vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H is consistent with a denial-of-service class flaw triggered by a malformed or specially crafted HTTP request reaching the server's request-handling layer.

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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:N/A:H
vuln.today AI 7.5 HIGH

Network-reachable unauthenticated HTTP attack with no credential requirement and impact limited solely to availability; no scope change, confidentiality, or integrity impact.

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

DescriptionCVE.org

Vulnerability in the Helidon product of Oracle Fusion Middleware (component: Imperative Web Server). The supported version that is affected is 3.2.19. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP 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).

Executive ViewAI

Why It Matters

Oracle Helidon 3.2.19 contains an unauthenticated denial-of-service vulnerability allowing any remote attacker to crash or hang the Imperative Web Server component with trivial HTTP requests, causing total service loss. With no vendor patch available, organizations running this version face immediate and unmitigated operational risk affecting any application dependent on Helidon. Any internet-facing or network-accessible instance requires emergency access controls to prevent attacker-triggered outages.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations include network segmentation to restrict HTTP access to authorized sources, Web Application Firewall (WAF) rules filtering malformed requests, aggressive connection rate-limiting and throttling, and enhanced monitoring for exploitation attempts. These controls substantially reduce exploitability but do not eliminate the vulnerability; upgrade or platform migration is required for complete remediation.

Threat Intelligence Overview

EPSS Score
0.3%
Top 75% exploitable
Prevalence
Low
niche Oracle microservice framework, limited mainstream enterprise adoption
Data Quality
6 sources
Confidence: High

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

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