# CVE-2011-2821: Use after free in n/a

> Remote attackers can cause denial of service or potentially execute code via crafted XPath expressions in libxml2 used by Chrome.

- **Severity:** High 7.5 (`AV:N/AC:L/Au:N/C:P/I:P/A:P`)
- **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:** 29 Aug 2011
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2011-2821, GHSA-mx3h-88ww-4mqq

## What is CVE-2011-2821?

CVE-2011-2821 is a high-severity use after free vulnerability in Apple Iphone Os, published on 29 Aug 2011. 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

Double free vulnerability in libxml2, as used in Google Chrome before 13.0.782.215, allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted XPath expression.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2011-2821?

It affects 8 products.


Products: Apple Iphone Os, Apple Mac Os X, Debian Debian Linux, Google Chrome, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server, Redhat Enterprise Linux Workstation.

## How do I fix CVE-2011-2821?

Upgrade to a fixed version.

## Is CVE-2011-2821 being exploited?

There is no known exploitation of CVE-2011-2821 in the wild and no public exploit code.

## 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-2016-4657](https://insights.sbomify.com/CVE-2016-4657/): Apple iOS Webkit Memory Corruption (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)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-2821 and fix it if it is affected.

What it is: CVE-2011-2821 is a high-severity use after free vulnerability in Apple Iphone Os, published on 29 Aug 2011. 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-2011-2821 in the wild and no public exploit code.

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-2011-2821/ (Markdown: https://insights.sbomify.com/CVE-2011-2821/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-2821
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-2821
- OSV: https://osv.dev/vulnerability/CVE-2011-2821

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-2821/
Summaries are generated and may contain mistakes; the official description above is the record.