# CVE-2021-30900: Apple iOS, iPadOS, and macOS Out-of-Bounds Write

> A malicious application can execute arbitrary code with kernel privileges due to an out-of-bounds write vulnerability in iOS and iPadOS.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 30 Mar 2023 (CISA KEV)
- **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:** 24 Aug 2021
- **Updated:** 21 Oct 2025

## What is CVE-2021-30900?

CVE-2021-30900 is a high-severity memory corruption vulnerability in Apple Ipados, published on 24 Aug 2021. 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

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 14.8.1 and iPadOS 14.8.1, iOS 15.1 and iPadOS 15.1. A malicious application may be able to execute arbitrary code with kernel privileges.

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

## Which versions are affected by CVE-2021-30900?

It affects 3 products.


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

## How do I fix CVE-2021-30900?

No fix has been published for CVE-2021-30900 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 20 Apr 2023.

## Is CVE-2021-30900 being exploited?

Yes. Attackers have exploited CVE-2021-30900 in the wild since at least 30 Mar 2023.

## 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-2021-30900 and fix it if it is affected.

What it is: CVE-2021-30900 is a high-severity memory corruption vulnerability in Apple Ipados, published on 24 Aug 2021. 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: Yes. Attackers have exploited CVE-2021-30900 in the wild since at least 30 Mar 2023.

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-2021-30900/ (Markdown: https://insights.sbomify.com/CVE-2021-30900/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-30900
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-30900
- OSV: https://osv.dev/vulnerability/CVE-2021-30900

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-30900/
Summaries are generated and may contain mistakes; the official description above is the record.