---
id: "CVE-2026-101569"
kind: "vulnerability"
aliases: ["CVE-2026-101569"]
title: "Helidon: concurrency-limits flaw allows unauthenticated data changes and partial denial of service"
severity: "medium"
cvss: 6.5
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["helidon", "java", "oracle-fusion-middleware", "runtime", "self-hosted"]
not_affected_if: ["not-helidon", "outside-affected-versions"]
published_at: "2026-10-20T22:18:09+00:00"
first_seen_at: "2026-10-23T21:57:22+00:00"
updated_at: "2026-10-25T03:55:16+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-101569", "first_seen_at": "2026-10-23T21:57:22+00:00"}]
---

# Helidon: concurrency-limits flaw allows unauthenticated data changes and partial denial of service

Oracle's Helidon Java framework has a flaw in its concurrency-limits component that lets an unauthenticated remote attacker send HTTP requests that change or delete some data the service can access and partly disrupt the service. The attack needs no login and no user action, and the CVSS base score is 6.5 (medium).

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the Helidon version in the project's dependency file for `helidon-common-concurrency-limits` or the Helidon BOM; affected versions are `4.0.0` through `4.5.5` and `27.0.0`
- Check whether the application uses the concurrency-limits feature (unknown whether it is on by default)

## Fix

- Upgrade Helidon to a version that includes the Oracle fix (the patched version is unknown from the sources; check Oracle's Critical Patch Update advisory for the Helidon fixed release)
- Rebuild and redeploy applications after updating the dependency

## Timeline

- 2026-10-23T21:57:22+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-101569

## From the sources

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).

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