# CVE-2020-14356: Null dereference in Kernel

> A local attacker can exploit a null pointer dereference in the Linux kernel cgroupv2 subsystem to crash the system or escalate privileges.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 19 Aug 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-14356, GHSA-gm74-x573-mg64, ROOT-OS-UBUNTU-2204-CVE-2020-14356, ROOT-OS-UBUNTU-2404-CVE-2020-14356, UBUNTU-CVE-2020-14356, USN-4484-1

## What is CVE-2020-14356?

CVE-2020-14356 is a high-severity vulnerability in Canonical Ubuntu Linux, published on 19 Aug 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw null pointer dereference in the Linux kernel cgroupv2 subsystem in versions before 5.7.10 was found in the way when reboot the system. A local user could use this flaw to crash the system or escalate their privileges on the system.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2020-14356?

It affects 10 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Linux kernel, Netapp Active Iq Unified Manager, Netapp Cloud Backup, Netapp Hci Management Node, Netapp Solidfire, Netapp Solidfire Baseboard Management Controller Firmware, Opensuse Leap, Redhat Enterprise Linux.

## How do I fix CVE-2020-14356?

Apply the vendor's patch.

## Is CVE-2020-14356 being exploited?

There is no known exploitation of CVE-2020-14356 in the wild and no public exploit code.

Public exploit code:

- https://github.com/ShaikUsaf/linux-4.19.72_CVE-2020-14356 (github_poc): https://github.com/ShaikUsaf/linux-4.19.72_CVE-2020-14356

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-14356 and fix it if it is affected.

What it is: CVE-2020-14356 is a high-severity vulnerability in Canonical Ubuntu Linux, published on 19 Aug 2020. 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-2020-14356 in the wild and no public exploit code.

Affected product: Canonical Ubuntu 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-2020-14356/ (Markdown: https://insights.sbomify.com/CVE-2020-14356/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-14356
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-14356
- OSV: https://osv.dev/vulnerability/CVE-2020-14356

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-14356/
Summaries are generated and may contain mistakes; the official description above is the record.