# CVE-2021-1789: Apple Multiple Products Type Confusion

> Attackers can execute arbitrary code by tricking users into visiting malicious web content in Safari or other WebKit-based apps on Apple devices.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 4 May 2022 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 2 Apr 2021
- **Updated:** 21 Oct 2025
- **Also known as:** DEBIAN-CVE-2021-1789, GHSA-c838-pj7m-89q4, UBUNTU-CVE-2021-1789

## What is CVE-2021-1789?

CVE-2021-1789 is a high-severity memory corruption vulnerability in Apple Ipados, published on 2 Apr 2021. 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

A type confusion issue was addressed with improved state handling. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. Processing maliciously crafted web content may lead to arbitrary code execution.

Weakness: CWE-843 (Access of Resource Using Incompatible Type)

## Which versions are affected by CVE-2021-1789?

It affects 8 products.


Products: Apple Ipados, Apple Iphone Os, Apple Mac Os X, Apple Macos, Apple Tvos, Apple Watchos, Fedoraproject Fedora, Webkitgtk Webkitgtk.

## How do I fix CVE-2021-1789?

Upgrade to a fixed version. US federal agencies must fix it by 25 May 2022.

## Is CVE-2021-1789 being exploited?

Yes. Attackers have exploited CVE-2021-1789 in the wild since at least 4 May 2022.

## 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-2021-1789 and fix it if it is affected.

What it is: CVE-2021-1789 is a high-severity memory corruption vulnerability in Apple Ipados, published on 2 Apr 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: Yes. Attackers have exploited CVE-2021-1789 in the wild since at least 4 May 2022.

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-2021-1789/ (Markdown: https://insights.sbomify.com/CVE-2021-1789/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-1789
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-1789
- OSV: https://osv.dev/vulnerability/CVE-2021-1789

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-1789/
Summaries are generated and may contain mistakes; the official description above is the record.