CVE-2026-83276

Analyzed Analyzed - Analysis Complete

Denial of Service in Helidon WebClient HTTP/2

Publication date: 2026-09-15

Last updated on: 2026-09-28

Assigner: Oracle

Description

Vulnerability in the Helidon product of Oracle Fusion Middleware (component: helidon-webclient-http2). Supported versions that are affected are 4.0.0-4.5.4. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP/2 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).

CVSS Scores

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Meta Information

Published

2026-09-15

Last Modified

2026-09-28

Generated

2026-10-06

AI Q&A

2026-09-16

EPSS Evaluated

2026-10-04

NVD

CVE-2026-83276

EUVD

EUVD-2026-79628

Affected Vendors & Products

Vendor	Product	Version / Range
oracle	helidon	From 4.0.0 (inc) to 4.5.4 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-400	The product does not properly control the allocation and maintenance of a limited resource.

Attack-Flow Graph

Executive Summary

This is a denial-of-service (DoS) vulnerability in Oracle Helidon's HTTP/2 web client component affecting versions 4.0.0 to 4.5.4. An unauthenticated attacker can remotely exploit it by sending specially crafted HTTP/2 requests to crash or hang the system repeatedly.

Detection Guidance

To detect this vulnerability, monitor for crashes or hangs in Helidon applications using HTTP/2. Check logs for repeated crashes in versions 4.0.0-4.5.4. Use network monitoring tools to inspect HTTP/2 traffic for malformed requests targeting Helidon services.

Impact Analysis

If you use affected Helidon versions, an attacker could disrupt service availability by causing crashes or hangs, leading to downtime for applications relying on Helidon's HTTP/2 functionality.

Compliance Impact

This vulnerability causes a denial-of-service condition in Oracle Helidon, leading to system unavailability. Such disruptions can impact compliance with regulations like GDPR (data processing delays) and HIPAA (service interruptions affecting protected health information access).

Mitigation Strategies

Upgrade Helidon to a version later than 4.5.4 as this vulnerability affects versions 4.0.0 to 4.5.4. If immediate upgrade is not possible, restrict network access to HTTP/2 ports or disable HTTP/2 support in Helidon to prevent exploitation.

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