# CVE-2021-1817: Memory corruption in iOS and iPadOS

> Attackers can execute arbitrary code by tricking users into visiting malicious web content 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:** 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:** 8 Sep 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-1817, GHSA-wm9j-fw55-hv9g, UBUNTU-CVE-2021-1817

## What is CVE-2021-1817?

CVE-2021-1817 is a high-severity memory corruption vulnerability in Apple Ipados, published on 8 Sep 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 memory corruption issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. Processing maliciously crafted web content may lead to arbitrary code execution.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-1817?

It affects 5 products.


Products: Apple Ipados, Apple Iphone Os, Apple Macos, Apple Tvos, Apple Watchos.

## How do I fix CVE-2021-1817?

Upgrade to a fixed version.

## Is CVE-2021-1817 being exploited?

There is no known exploitation of CVE-2021-1817 in the wild and no public exploit code.

## 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-2021-1817 and fix it if it is affected.

What it is: CVE-2021-1817 is a high-severity memory corruption vulnerability in Apple Ipados, published on 8 Sep 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: There is no known exploitation of CVE-2021-1817 in the wild and no public exploit code.

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-2021-1817/ (Markdown: https://insights.sbomify.com/CVE-2021-1817/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-1817
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-1817
- OSV: https://osv.dev/vulnerability/CVE-2021-1817

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-1817/
Summaries are generated and may contain mistakes; the official description above is the record.