# CVE-2021-33135: Denial of service in Intel(R) SGX

> An authenticated local user can cause a denial of service in the Linux kernel via uncontrolled resource consumption in Intel SGX drivers.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 May 2022
- **Updated:** 5 May 2025
- **Also known as:** DEBIAN-CVE-2021-33135, GHSA-q2pr-ffxw-p47h, UBUNTU-CVE-2021-33135

## What is CVE-2021-33135?

CVE-2021-33135 is a medium-severity denial of service vulnerability in Intel(R) SGX, published on 12 May 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Uncontrolled resource consumption in the Linux kernel drivers for Intel(R) SGX may allow an authenticated user to potentially enable denial of service via local access.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2021-33135?

It affects 1 product.


Products: Intel Software Guard Extensions.

## How do I fix CVE-2021-33135?

Apply the vendor's patch.

## Is CVE-2021-33135 being exploited?

There is no known exploitation of CVE-2021-33135 in the wild and no public exploit code.

## Other vulnerabilities in Intel(R) SGX

- [CVE-2019-0157](https://insights.sbomify.com/CVE-2019-0157/): Denial of service in Intel(R) SGX for Linux (medium 5.5)
- [CVE-2018-3689](https://insights.sbomify.com/CVE-2018-3689/): Denial of service in Guard Extensions Platform Software Component for Linux (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33135 and fix it if it is affected.

What it is: CVE-2021-33135 is a medium-severity denial of service vulnerability in Intel(R) SGX, published on 12 May 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-33135 in the wild and no public exploit code.

Affected product: Intel(R) SGX. 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-2021-33135/ (Markdown: https://insights.sbomify.com/CVE-2021-33135/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33135
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33135
- OSV: https://osv.dev/vulnerability/CVE-2021-33135

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-33135/
Summaries are generated and may contain mistakes; the official description above is the record.