# CVE-2021-3744: Denial of service in kernel

> Attackers can cause a denial of service via memory consumption in the Linux kernel's CCP crypto driver due to a memory leak.

- **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:** 4 Mar 2022
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-3744, UBUNTU-CVE-2021-3744

## What is CVE-2021-3744?

CVE-2021-3744 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 4 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A memory leak flaw was found in the Linux kernel in the ccp_run_aes_gcm_cmd() function in drivers/crypto/ccp/ccp-ops.c, which allows attackers to cause a denial of service (memory consumption). This vulnerability is similar with the older CVE-2019-18808.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2021-3744?

It affects 23 products.


Products: Debian Debian Linux, Fedoraproject Fedora, Linux kernel, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Network Exposure Function, Oracle Communications Cloud Native Core Policy, Redhat Build of Quarkus, Redhat Codeready Linux Builder, Redhat Codeready Linux Builder Eus, Redhat Codeready Linux Builder for Power Little Endian, Redhat Codeready Linux Builder for Power Little Endian Eus, Redhat Developer Tools, Redhat Enterprise Linux Eus, Redhat Enterprise Linux for Ibm Z Systems Eus, Redhat Enterprise Linux for Power Little Endian Eus, Redhat Enterprise Linux for Real Time, Redhat Enterprise Linux for Real Time for Nfv, Redhat Enterprise Linux for Real Time for Nfv Tus, Redhat Enterprise Linux Server Eus, Redhat Enterprise Linux Server for Power Little Endian Update Services for Sap Solutions and 3 more.

## How do I fix CVE-2021-3744?

Apply the vendor's patch.

## Is CVE-2021-3744 being exploited?

There is no known exploitation of CVE-2021-3744 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3744 and fix it if it is affected.

What it is: CVE-2021-3744 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 4 Mar 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-2021-3744 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2021-3744/ (Markdown: https://insights.sbomify.com/CVE-2021-3744/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3744
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3744
- OSV: https://osv.dev/vulnerability/CVE-2021-3744

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3744/
Summaries are generated and may contain mistakes; the official description above is the record.