# CVE-2016-9899: Use after free in Firefox

> A use-after-free flaw in Firefox allows attackers to execute arbitrary code via crafted DOM events and audio elements.

- **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:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-9899, GHSA-q3mj-v3xc-w732, UBUNTU-CVE-2016-9899

## What is CVE-2016-9899?

CVE-2016-9899 is a critical use after free vulnerability in Debian Debian 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

Use-after-free while manipulating DOM events and removing audio elements due to errors in the handling of node adoption. This vulnerability affects Firefox < 50.1, Firefox ESR < 45.6, and Thunderbird < 45.6.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2016-9899?

It affects 9 products.


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

## How do I fix CVE-2016-9899?

Upgrade to a fixed version.

## Is CVE-2016-9899 being exploited?

There is no known exploitation of CVE-2016-9899 in the wild and no public exploit code.

Public exploit code:

- Mozilla Firefox < 50.1.0 - Use-After-Free (exploitdb)

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-9899 and fix it if it is affected.

What it is: CVE-2016-9899 is a critical use after free vulnerability in Debian Debian Linux, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2016-9899 in the wild and no public exploit code.

Affected product: Debian Debian 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-2016-9899/ (Markdown: https://insights.sbomify.com/CVE-2016-9899/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-9899
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-9899
- OSV: https://osv.dev/vulnerability/CVE-2016-9899

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-9899/
Summaries are generated and may contain mistakes; the official description above is the record.