# CVE-2020-9839: Race condition in iOS

> A race condition in Apple operating systems allows an application to gain elevated privileges, requiring users to update their devices.

- **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/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:** No
- **Published:** 9 Jun 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-38pp-34cq-8xpr

## What is CVE-2020-9839?

CVE-2020-9839 is a high-severity vulnerability in Apple Ipados, published on 9 Jun 2020. 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

A race condition was addressed with improved state handling. This issue is fixed in iOS 13.5 and iPadOS 13.5, macOS Catalina 10.15.5, tvOS 13.4.5, watchOS 6.2.5. An application may be able to gain elevated privileges.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2020-9839?

It affects 5 products.


Products: Apple Ipados, Apple Iphone Os, Apple Mac Os X, Apple Tvos, Apple Watchos.

## How do I fix CVE-2020-9839?

No fix has been published for CVE-2020-9839 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-9839 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-9839 exists.

Public exploit code:

- macOS cfprefsd Arbitrary File Write Local Privilege Escalation (metasploit)

## Other vulnerabilities in Apple Ipados

- [CVE-2025-43300](https://insights.sbomify.com/CVE-2025-43300/): Apple iOS, iPadOS, and macOS Out-of-Bounds Write (critical 10.0, exploited in the wild)
- [CVE-2025-24201](https://insights.sbomify.com/CVE-2025-24201/): Apple Multiple Products WebKit Out-of-Bounds Write (critical 10.0, exploited in the wild)
- [CVE-2025-24085](https://insights.sbomify.com/CVE-2025-24085/): Apple Multiple Products Use-After-Free (critical 10.0, exploited in the wild)
- [CVE-2025-31200](https://insights.sbomify.com/CVE-2025-31200/): Apple Multiple Products Memory Corruption (critical 9.8, exploited in the wild)
- [CVE-2025-31201](https://insights.sbomify.com/CVE-2025-31201/): Apple Multiple Products Arbitrary Read and Write (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-9839 and fix it if it is affected.

What it is: CVE-2020-9839 is a high-severity vulnerability in Apple Ipados, published on 9 Jun 2020. 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-9839 exists.

Affected product: Apple Ipados. 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-2020-9839/ (Markdown: https://insights.sbomify.com/CVE-2020-9839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-9839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-9839
- OSV: https://osv.dev/vulnerability/CVE-2020-9839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-9839/
Summaries are generated and may contain mistakes; the official description above is the record.