---
id: CVE-2026-72657
title: >-
  Authorization Bypass Through User-Controlled Key (CWE-639) in Fleet Server can
  lead to information disclosure via Manipulating User-Controlled Variables
  (CAPEC-77)
summary: >-
  Authorization Bypass Through User-Controlled Key (CWE-639) in Fleet Server can
  lead to information disclosure via Manipulating User-Controlled Variables
  (CAPEC-77). The authorization decision for artifact downloads relied on a
  client-sup…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-639
vendor: elastic
product: fleet_server
affected:
  - 'fleet_server >= 8.3.0, < 8.19.20'
  - 'fleet_server >= 9.0.0, < 9.4.5'
  - fleet_server = 9.5.0
patched:
  - fleet_server 9.4.5
published: '2026-08-13'
updated: '2026-09-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72657'
references:
  - url: >-
      https://discuss.elastic.co/t/fleet-server-8-19-20-9-4-5-9-5-1-security-update-esa-2026-112/389509
    label: security@elastic.co
tags:
  - nvd
epss: 0.00385
epssPercentile: 0.29812
ingestedAt: '2026-09-05T18:43:14.288Z'
---

## Overview

Authorization Bypass Through User-Controlled Key (CWE-639) in Fleet Server can lead to information disclosure via Manipulating User-Controlled Variables (CAPEC-77). The authorization decision for artifact downloads relied on a client-supplied value that was persisted without being validated against the server-side record of the requesting agent's assignment. An authenticated party in possession of a valid enrolled agent credential could therefore retrieve a policy the agent is not assigned to.

## Affected

- `fleet_server >= 8.3.0, < 8.19.20`
- `fleet_server >= 9.0.0, < 9.4.5`
- `fleet_server = 9.5.0`

## Remediation

Upgrade past the affected range:

- `fleet_server 9.4.5`