# CVE-2026-33521: BUG-000186514 - ArcGIS Server has a security vulnerability.


- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 26 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** GHSA-wc5q-3mff-vvxv

## What is CVE-2026-33521?

CVE-2026-33521 is a high-severity vulnerability in Esri ArcGIS Server, published on 26 Oct 2026. 

### Official description

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.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-33521?


## How do I fix CVE-2026-33521?

No fix has been published for CVE-2026-33521 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-33521 being exploited?

There is no known exploitation of CVE-2026-33521 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33521 and fix it if it is affected.

What it is: CVE-2026-33521 is a high-severity vulnerability in Esri ArcGIS Server, published on 26 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-33521 in the wild and no public exploit code.

Affected product: Esri ArcGIS Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-33521/ (Markdown: https://insights.sbomify.com/CVE-2026-33521/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33521
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33521
- OSV: https://osv.dev/vulnerability/CVE-2026-33521

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33521/
Summaries are generated and may contain mistakes; the official description above is the record.