# CVE-2016-4657: Apple iOS Webkit Memory Corruption

> Remote attackers can execute arbitrary code or cause denial of service via a crafted website due to memory corruption in WebKit on iOS.

- **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 24 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:** 25 Aug 2016
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-99xm-29ff-vvqm, UBUNTU-CVE-2016-4657

## What is CVE-2016-4657?

CVE-2016-4657 is a high-severity memory corruption vulnerability in Apple Iphone Os, published on 25 Aug 2016. 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

WebKit in Apple iOS before 9.3.5 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.

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

## Which versions are affected by CVE-2016-4657?

It affects 1 product.


Products: Apple Iphone Os.

## How do I fix CVE-2016-4657?

Upgrade to a fixed version. US federal agencies must fix it by 14 Jun 2022.

## Is CVE-2016-4657 being exploited?

Yes. Attackers have exploited CVE-2016-4657 in the wild since at least 24 May 2022.

Public exploit code:

- Exploiting CVE-2016-4657 to JailBreak the Nintendo Switch (github_poc): https://github.com/iDaN5x/Switcheroo
-  CVE-2016-4657 web-kit vulnerability for  ios 9.3, nintendo switch browser vulnerability   (github_poc): https://github.com/viai957/webkit-vulnerability
- CVE-2016-4657 for NintendoSwitch rwx (github_poc): https://github.com/Mimoja/CVE-2016-4657-NintendoSwitch
- WebKit not_number defineProperties UAF (metasploit)
- Nintendo Switch - WebKit Code Execution (PoC) (exploitdb)
- WebKit - not_number defineProperties UAF (Metasploit) (exploitdb)

## Other vulnerabilities in Apple Iphone Os

- [CVE-2021-30666](https://insights.sbomify.com/CVE-2021-30666/): Apple iOS WebKit Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2021-30761](https://insights.sbomify.com/CVE-2021-30761/): Apple iOS WebKit Memory Corruption (high 8.8, exploited in the wild)
- [CVE-2021-30762](https://insights.sbomify.com/CVE-2021-30762/): Apple iOS WebKit Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2019-7286](https://insights.sbomify.com/CVE-2019-7286/): Apple Multiple Products Memory Corruption (high 7.8, exploited in the wild)
- [CVE-2019-7287](https://insights.sbomify.com/CVE-2019-7287/): Apple iOS Memory Corruption (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-4657 and fix it if it is affected.

What it is: CVE-2016-4657 is a high-severity memory corruption vulnerability in Apple Iphone Os, published on 25 Aug 2016. 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-2016-4657 in the wild since at least 24 May 2022.

Affected product: Apple Iphone Os. 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-2016-4657/ (Markdown: https://insights.sbomify.com/CVE-2016-4657/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-4657
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-4657
- OSV: https://osv.dev/vulnerability/CVE-2016-4657

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From sbomify Insights: https://insights.sbomify.com/CVE-2016-4657/
Summaries are generated and may contain mistakes; the official description above is the record.