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Oracle Helidon CVE-2026-101569

| EUVDEUVD-2026-105977 MEDIUM
Improper Access Control (CWE-284)
2026-10-20 secalert_us@oracle.com GHSA-hv68-q6jh-26xg
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
    Reach Helidon HTTP endpoint over network
  2. Delivery
    Send crafted requests abusing concurrency limits
  3. Exploit
    Bypass throttling / rate controls
  4. Execution
    Exhaust capacity and tamper with data
  5. Impact
    Partial DoS and unauthorized data modification

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 conditions - remote unauthenticated exploitation over HTTP against default configurations of Oracle Helidon in affected versions (4.0.0 through 4.5.5, and 27.0.0), consistent with AV:N/AC:L/PR:N/UI:N. Exploitation requires only that the Helidon service expose an HTTP endpoint reachable by the attacker and that it uses the helidon-common-concurrency-limits component. Limiting factors: impact is bounded (no confidentiality loss, only partial integrity and partial availability), the scope is unchanged (no pivot beyond the Helidon process), and environments on unaffected/patched versions or that restrict network reachability to the service are not exposed.

Impact

This is a moderate-severity issue (CVSS 3.1 base 6.5) driven by a favorable attack profile rather than high impact: the Oracle-supplied vector (AV:N/AC:L/PR:N/UI:N) indicates a network-reachable, low-complexity, unauthenticated, no-user-interaction flaw, which maximizes exploitability, but the impact is capped at partial integrity (I:L) and partial availability (A:L) with no confidentiality loss (C:N) and no scope change (S:U). The affected component (helidon-common-concurrency-limits) and the 'Denial Of Service' tag suggest the real-world effect is bypassing or exhausting concurrency/rate-limiting controls, enabling a partial DoS and limited unauthorized data modification. No EPSS score, no CISA KEV listing, and no public POC were provided, so there is no evidence of active or imminent exploitation; the only exploitation signal is the inherently easy attack vector asserted by the vendor. Net assessment: a credible, easy-to-reach vulnerability worth patching in the normal Oracle CPU cycle, but NOT an emergency - treat as medium priority absent any exploitation telemetry. Key missing data: no EPSS probability and no KEV/POC status to confirm whether this is being targeted; CWE is listed as N/A, so the precise weakness class is unconfirmed.

Exploit ScenarioDerived

An unauthenticated attacker with network access sends crafted HTTP requests to a Helidon service to abuse the concurrency-limits component, bypassing throttling controls to exhaust server capacity and cause a partial denial of service, while also achieving limited unauthorized modification of some Helidon-accessible data. Because the CVSS vector is AV:N/AC:L/PR:N/UI:N, no credentials, user interaction, or special timing are needed. No public exploit code was identified in the provided intelligence.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 21, 2026

Unauthenticated HTTP requests against Oracle Helidon 4.0.0 through 4.5.5 and 27.0.0 can alter or delete some Helidon-accessible data and partially degrade service availability, with the fault residing in the helidon-common-concurrency-limits component. The disclosed vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L, base 6.5) means no credentials or user interaction are needed, but impact is capped at low integrity and low availability with no confidentiality loss and no scope change, so the risk derives from the easy attack profile rather than severe consequences. No public exploit identified at time of analysis, and the issue is not listed in CISA KEV; Oracle addresses it through its October 2026 Critical Patch Update.

RemediationAI

Patch available per vendor advisory: Oracle fixes this in its Critical Patch Update for October 2026 (https://www.oracle.com/security-alerts/cpuoct2026.html), so upgrade Helidon off the affected ranges 4.0.0-4.5.5 and 27.0.0 to the fixed release Oracle names for your line, then rebuild and redeploy dependent services and verify the helidon-common-concurrency-limits artifact version in the resolved dependency tree (transitive pulls are common). Because exploitation is a plain unauthenticated HTTP request, the most effective interim control is to restrict network reachability of the Helidon listener - front it with an API gateway or ingress policy that allow-lists trusted client networks, or require mTLS at the edge - accepting the operational cost that legitimate external or partner clients must be re-onboarded through the new path. Where the concurrency-limiting endpoint or configuration surface is separately addressable, disabling or firewalling administrative/limit-tuning routes reduces exposure at the price of losing dynamic limit adjustment. Tighten and monitor WAF/gateway rules for anomalous request bursts or unexpected write-shaped calls to limit-related paths, and alert on 5xx/latency spikes that would signal the partial-DoS component; note that lowering global concurrency limits as a stopgap reduces peak throughput for all tenants. Environments that cannot patch promptly should treat the service as untrusted-network-exposed until the upgrade is applied.

Affected VersionsENISA

Helidon 4.0.0 ≤4.5.5
Helidon 27.0.0

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 set of Java libraries and a lightweight runtime for building microservices, offered in both Helidon SE (reactive, non-blocking) and Helidon MP (MicroProfile/ Jakarta EE) flavors within Oracle Fusion Middleware. The vulnerable module, helidon-common-concurrency-limits, is the shared concurrency-limiting layer used to bound in-flight work and shed load - the Helidon analogue of bulkhead/adaptive concurrency-limit patterns (conceptually related to Netflix's concurrency-limits library). Because the flaw sits in this common limiting layer, the exposure surface is any Helidon service whose HTTP stack routes requests through the component, and the weakness appears to allow a remote caller to influence or bypass the intended limit accounting, producing unintended state changes in Helidon-accessible data plus partial denial of service. No CWE identifier was assigned in the provided data, so the precise root-cause class (for example improper handling of concurrent state, limit-bypass logic, or insufficient validation of request-derived limit parameters) is not confirmed from available sources. EUVD lists the affected ranges as Helidon 4.0.0 ≤ 4.5.5 and 27.0.0; no CPE strings were supplied, so exact platform/build bindings should be confirmed against the Oracle CPU October 2026 advisory.

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Severity by source

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

Vendor description confirms unauthenticated HTTP-reachable, low-complexity attack (AV:N/AC:L/PR:N/UI:N) with no confidentiality loss and only partial integrity and availability impact.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/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
Low
Availability
Low

DescriptionCVE.org

Vulnerability in the Helidon product of Oracle Fusion Middleware (component: helidon-common-concurrency-limits). Supported versions that are affected are 4.0.0-4.5.5 and 27.0.0. 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 and unauthorized ability to cause a partial denial of service (partial DOS) of Helidon. CVSS 3.1 Base Score 6.5 (Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L).

Threat Intelligence Overview

EPSS Score
0.4%
Top 73% exploitable
Prevalence
Low
Oracle's open-source Java microservices framework, niche adoption versus Spring
Data Quality
4 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 0.4%
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· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

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.

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

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