---
id: "CVE-2026-101586"
kind: "vulnerability"
aliases: ["CVE-2026-101586"]
title: "Helidon: unauthenticated network attacker gets read access to some data"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["helidon", "java", "oracle-fusion-middleware", "runtime", "self-hosted"]
not_affected_if: ["other-versions"]
published_at: "2026-10-20T22:18:12+00:00"
first_seen_at: "2026-10-23T21:57:22+00:00"
updated_at: "2026-10-25T04:23:17+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-101586", "first_seen_at": "2026-10-23T21:57:22+00:00"}]
---

# Helidon: unauthenticated network attacker gets read access to some data

Helidon's webclient component, part of Oracle Fusion Middleware, has a flaw in versions 4.0.0 through 4.5.5 and 27.0.0. An unauthenticated attacker with network access over HTTP can read a subset of data the Helidon application can access.

_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 example, the `io.helidon` version in Maven or Gradle) and see whether it falls in `4.0.0` to `4.5.5` or is `27.0.0`.
- unknown for whether a specific deployment uses helidon-webclient in a reachable path.

## Fix

- Move Helidon to a release outside the affected range `4.0.0` to `4.5.5` and `27.0.0`; the fixed version is unknown from the sources.
- unknown for any configuration workaround.

## Timeline

- 2026-10-23T21:57:22+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-101586

## From the sources

Vulnerability in the Helidon product of Oracle Fusion Middleware (component: helidon-webclient).  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 read access to a subset of Helidon accessible data. CVSS 3.1 Base Score 5.3 (Confidentiality impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_