# CVE-2011-0420: Null dereference in n/a

> Attackers can cause a denial of service via a crash in the PHP Intl extension's grapheme_extract function due to a NULL pointer dereference.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Feb 2011
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-78j2-xvgc-hm94

## What is CVE-2011-0420?

CVE-2011-0420 is a medium-severity vulnerability in Php Php, published on 18 Feb 2011. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The grapheme_extract function in the Internationalization extension (Intl) for ICU for PHP 5.3.5 allows context-dependent attackers to cause a denial of service (crash) via an invalid size argument, which triggers a NULL pointer dereference.

## Which versions are affected by CVE-2011-0420?

It affects 1 product.


Products: Php Php.

## How do I fix CVE-2011-0420?

Upgrade to a fixed version.

## Is CVE-2011-0420 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2011-0420 exists.

Public exploit code:

- PHP 5.3.5 - 'grapheme_extract()' Null Pointer Dereference (exploitdb)
- PHP 5.3.5 - 'grapheme_extract()' Null Pointer Dereference Denial of Service (exploitdb)

## Other vulnerabilities in Php Php

- [CVE-2012-2688](https://insights.sbomify.com/CVE-2012-2688/): Integer overflow in n/a (critical 10.0)
- [CVE-2012-2376](https://insights.sbomify.com/CVE-2012-2376/): Memory corruption in n/a (critical 10.0)
- [CVE-2011-3268](https://insights.sbomify.com/CVE-2011-3268/): Memory corruption in n/a (critical 10.0)
- [CVE-2009-4143](https://insights.sbomify.com/CVE-2009-4143/): Other in n/a (critical 10.0)
- [CVE-2008-5557](https://insights.sbomify.com/CVE-2008-5557/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-0420 and fix it if it is affected.

What it is: CVE-2011-0420 is a medium-severity vulnerability in Php Php, published on 18 Feb 2011. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2011-0420 exists.

Affected product: Php Php. 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-2011-0420/ (Markdown: https://insights.sbomify.com/CVE-2011-0420/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-0420
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-0420
- OSV: https://osv.dev/vulnerability/CVE-2011-0420

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-0420/
Summaries are generated and may contain mistakes; the official description above is the record.