# CVE-2020-11931: Ubuntu modifications to pulseaudio to provide snap security enforcement could be unloaded

> Attackers can bypass Ubuntu Snap security restrictions for audio access by unloading the PulseAudio policy module, affecting Ubuntu systems.

- **Severity:** Low 3.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`)
- **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:** 15 May 2020
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-m777-7jfr-8wgh, UBUNTU-CVE-2020-11931, USN-4355-1

## What is CVE-2020-11931?

CVE-2020-11931 is a low-severity vulnerability in Canonical Ubuntu Linux, published on 15 May 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An Ubuntu-specific modification to Pulseaudio to provide security mediation for Snap-packaged applications was found to have a bypass of intended access restriction for snaps which plugs any of pulseaudio, audio-playback or audio-record via unloading the pulseaudio snap policy module. This issue affects: pulseaudio 1:8.0 versions prior to 1:8.0-0ubuntu3.12; 1:11.1 versions prior to 1:11.1-1ubuntu7.7; 1:13.0 versions prior to 1:13.0-1ubuntu1.2; 1:13.99.1 versions prior to 1:13.99.1-1ubuntu3.2;

Weakness: CWE-668 (Exposure of Resource to Wrong Sphere), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2020-11931?

It affects 2 products.


Products: Canonical Ubuntu Linux, Pulseaudio Pulseaudio.

## How do I fix CVE-2020-11931?

Apply the vendor's patch.

## Is CVE-2020-11931 being exploited?

There is no known exploitation of CVE-2020-11931 in the wild and no public exploit code.

## 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-2020-11931 and fix it if it is affected.

What it is: CVE-2020-11931 is a low-severity vulnerability in Canonical Ubuntu Linux, published on 15 May 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-2020-11931 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-2020-11931/ (Markdown: https://insights.sbomify.com/CVE-2020-11931/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-11931
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-11931
- OSV: https://osv.dev/vulnerability/CVE-2020-11931

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-11931/
Summaries are generated and may contain mistakes; the official description above is the record.