# CVE-2018-4209: Denial of service in n/a

> Unexpected interaction causes an assertion failure, leading to a denial of service in Apple operating systems and browsers.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 11 Jan 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-4209, GHSA-m9mv-7x4j-x2cw, UBUNTU-CVE-2018-4209

## What is CVE-2018-4209?

CVE-2018-4209 is a high-severity denial of service vulnerability in Apple Icloud, published on 11 Jan 2019. 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

In iOS before 11.3, Safari before 11.1, iCloud for Windows before 7.4, tvOS before 11.3, watchOS before 4.3, iTunes before 12.7.4 for Windows, unexpected interaction causes an ASSERT failure. This issue was addressed with improved checks.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2018-4209?

It affects 8 products.


Products: Apple Icloud, Apple Iphone Os, Apple Itunes, Apple Safari, Apple Tvos, Apple Watchos, Canonical Ubuntu Linux, Webkit Webkitgtk\+.

## How do I fix CVE-2018-4209?

Upgrade to a fixed version.

## Is CVE-2018-4209 being exploited?

There is no known exploitation of CVE-2018-4209 in the wild and no public exploit code.

## Other vulnerabilities in Apple Icloud

- [CVE-2019-8506](https://insights.sbomify.com/CVE-2019-8506/): Apple Multiple Products Type Confusion (high 8.8, exploited in the wild)
- [CVE-2020-27932](https://insights.sbomify.com/CVE-2020-27932/): Apple Multiple Products Type Confusion (high 7.8, exploited in the wild)
- [CVE-2019-8746](https://insights.sbomify.com/CVE-2019-8746/): Memory corruption in iOS (critical 9.8)
- [CVE-2019-8749](https://insights.sbomify.com/CVE-2019-8749/): Memory corruption in iOS (critical 9.8)
- [CVE-2019-8756](https://insights.sbomify.com/CVE-2019-8756/): Memory corruption in iOS (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-4209 and fix it if it is affected.

What it is: CVE-2018-4209 is a high-severity denial of service vulnerability in Apple Icloud, published on 11 Jan 2019. 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-2018-4209 in the wild and no public exploit code.

Affected product: Apple Icloud. 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-2018-4209/ (Markdown: https://insights.sbomify.com/CVE-2018-4209/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-4209
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-4209
- OSV: https://osv.dev/vulnerability/CVE-2018-4209

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-4209/
Summaries are generated and may contain mistakes; the official description above is the record.