# CVE-2018-5159: Integer overflow in Firefox

> An integer overflow in the Skia library allows attackers to trigger out-of-bounds writes via web content, potentially leading to code execution or crashes in Firefox and Thunderbird.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Jun 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-5159, GHSA-qchp-2hvj-gj3q, UBUNTU-CVE-2018-5159

## What is CVE-2018-5159?

CVE-2018-5159 is a critical vulnerability in Canonical Ubuntu Linux, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An integer overflow can occur in the Skia library due to 32-bit integer use in an array without integer overflow checks, resulting in possible out-of-bounds writes. This could lead to a potentially exploitable crash triggerable by web content. This vulnerability affects Thunderbird < 52.8, Thunderbird ESR < 52.8, Firefox < 60, and Firefox ESR < 52.8.

Weakness: CWE-787 (Out-of-bounds Write), CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2018-5159?

It affects 11 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Mozilla Firefox, Mozilla Thunderbird, Mozilla Thunderbird Esr, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus, Redhat Enterprise Linux Server Tus, Redhat Enterprise Linux Workstation.

## How do I fix CVE-2018-5159?

Upgrade to a fixed version.

## Is CVE-2018-5159 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-5159 exists.

Public exploit code:

- Skia and Firefox - Integer Overflow in SkTDArray Leading to Out-of-Bounds Write (exploitdb)
- Skia and Firefox - Integer Overflow in SkTDArray Leading to Out-of-Bounds Write (exploitdb)

## 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-2018-5159 and fix it if it is affected.

What it is: CVE-2018-5159 is a critical vulnerability in Canonical Ubuntu Linux, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-5159 exists.

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-2018-5159/ (Markdown: https://insights.sbomify.com/CVE-2018-5159/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-5159
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-5159
- OSV: https://osv.dev/vulnerability/CVE-2018-5159

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-5159/
Summaries are generated and may contain mistakes; the official description above is the record.