---
id: CVE-2026-33521
title: BUG-000186514 - ArcGIS Server has a security vulnerability.
summary: >-
  There is s denial of service vulnerability in Esri ArcGIS Server versions 12.0
  and prior that may allow a remote, unauthenticated attacker to supply crafted
  requests that may, under exceptional circumstances, consume all available
  worker…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-400
vendor: Esri
product: ArcGIS Server
affected:
  - arcgis_server >= 11.1 < 12.0
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-26T18:58:18.796884Z'
published: '2026-10-26'
updated: '2026-10-26'
sourceUpdated: '2026-10-26T19:38:29.004Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-33521'
references:
  - url: >-
      https://www.esri.com/arcgis-blog/products/trust-arcgis/administration/october-2026-arcgis-security-bulletin
tags:
  - cve.org
ingestedAt: '2026-10-26T18:35:51.492Z'
epss: 0.00448
epssPercentile: 0.39062
---

## Overview

There is s denial of service vulnerability in Esri ArcGIS Server versions 12.0 and prior that may allow a remote, unauthenticated attacker to supply crafted requests that may, under exceptional circumstances, consume all available worker threads and deny service to users. A patch is provided for ArcGIS Server software in General Availability and Extended support status, which includes versions 12.0, 11.5, 11.3, and 11.1. Other versions are in mature or retired status, which are not patch eligible. Users working with unlisted versions are advised to upgrade and apply the patch.

## Affected

- `arcgis_server >= 11.1 < 12.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.