# CVE-2018-5133: Cross-site scripting in Firefox

> A malicious local program can inject scripts into Firefox preferences, leading to code execution when specific UI elements are loaded.

- **Severity:** Medium 6.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 11 Jun 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-9rwp-r33f-q36c, UBUNTU-CVE-2018-5133

## What is CVE-2018-5133?

CVE-2018-5133 is a medium-severity cross-site scripting vulnerability in Canonical Ubuntu Linux, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

If the "app.support.baseURL" preference is changed by a malicious local program to contain HTML and script content, this content is not sanitized. It will be executed if a user loads "chrome://browser/content/preferences/in-content/preferences.xul" directly in a tab and executes a search. This stored preference is also executed whenever an EME video player plugin displays a CDM-disabled message as a notification message. This vulnerability affects Firefox < 59.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2018-5133?

It affects 2 products.


Products: Canonical Ubuntu Linux, Mozilla Firefox.

## How do I fix CVE-2018-5133?

Upgrade to a fixed version.

## Is CVE-2018-5133 being exploited?

There is no known exploitation of CVE-2018-5133 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-2018-5133 and fix it if it is affected.

What it is: CVE-2018-5133 is a medium-severity cross-site scripting vulnerability in Canonical Ubuntu Linux, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-5133 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-2018-5133/ (Markdown: https://insights.sbomify.com/CVE-2018-5133/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-5133
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-5133
- OSV: https://osv.dev/vulnerability/CVE-2018-5133

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-5133/
Summaries are generated and may contain mistakes; the official description above is the record.