# CVE-2021-31523: Privilege escalation in n/a

> Local attackers can escalate privileges due to excessive capabilities granted to the sonar binary in the Debian xscreensaver package.

- **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:** 21 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-31523, GHSA-74g6-fv7f-g2hq, UBUNTU-CVE-2021-31523

## What is CVE-2021-31523?

CVE-2021-31523 is a high-severity vulnerability in n/a, published on 21 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Debian xscreensaver 5.42+dfsg1-1 package for XScreenSaver has cap_net_raw enabled for the /usr/libexec/xscreensaver/sonar file, which allows local users to gain privileges because this is arguably incompatible with the design of the Mesa 3D Graphics library dependency.

Weakness: CWE-269 (Improper Privilege Management)

## Which versions are affected by CVE-2021-31523?

It affects 1 product.


Products: Xscreensaver Project Xscreensaver.

## How do I fix CVE-2021-31523?

Apply the vendor's patch.

## Is CVE-2021-31523 being exploited?

There is no known exploitation of CVE-2021-31523 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31523 and fix it if it is affected.

What it is: CVE-2021-31523 is a high-severity vulnerability in n/a, published on 21 Apr 2021. 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-2021-31523 in the wild and no public exploit code.

Affected product: n/a. 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-2021-31523/ (Markdown: https://insights.sbomify.com/CVE-2021-31523/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31523
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31523
- OSV: https://osv.dev/vulnerability/CVE-2021-31523

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31523/
Summaries are generated and may contain mistakes; the official description above is the record.