# CVE-2016-1836: Use after free in n/a

> Remote attackers can cause a denial of service via a crafted XML document due to a use-after-free flaw in libxml2.

- **Severity:** Medium 5.5 (`CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 20 May 2016
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-1836, GHSA-82c9-fqj6-w7gm, UBUNTU-CVE-2016-1836

## What is CVE-2016-1836?

CVE-2016-1836 is a medium-severity use after free vulnerability in Apple Iphone Os, published on 20 May 2016. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Use-after-free vulnerability in the xmlDictComputeFastKey function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to cause a denial of service via a crafted XML document.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2016-1836?

It affects 14 products.


Products: Apple Iphone Os, Apple Mac Os X, Apple Tvos, Apple Watchos, Canonical Ubuntu Linux, Debian Debian Linux, Mcafee Web Gateway, 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, Xmlsoft Libxml2.

## How do I fix CVE-2016-1836?

Upgrade to a fixed version.

## Is CVE-2016-1836 being exploited?

There is no known exploitation of CVE-2016-1836 in the wild and no public exploit code.

## Other vulnerabilities in Apple Iphone Os

- [CVE-2021-30666](https://insights.sbomify.com/CVE-2021-30666/): Apple iOS WebKit Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2021-30761](https://insights.sbomify.com/CVE-2021-30761/): Apple iOS WebKit Memory Corruption (high 8.8, exploited in the wild)
- [CVE-2021-30762](https://insights.sbomify.com/CVE-2021-30762/): Apple iOS WebKit Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2016-4657](https://insights.sbomify.com/CVE-2016-4657/): Apple iOS Webkit Memory Corruption (high 8.8, exploited in the wild)
- [CVE-2019-7286](https://insights.sbomify.com/CVE-2019-7286/): Apple Multiple Products Memory Corruption (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-1836 and fix it if it is affected.

What it is: CVE-2016-1836 is a medium-severity use after free vulnerability in Apple Iphone Os, published on 20 May 2016. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2016-1836 in the wild and no public exploit code.

Affected product: Apple Iphone Os. 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-2016-1836/ (Markdown: https://insights.sbomify.com/CVE-2016-1836/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-1836
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-1836
- OSV: https://osv.dev/vulnerability/CVE-2016-1836

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-1836/
Summaries are generated and may contain mistakes; the official description above is the record.