# CVE-2018-9956: Use after free in Foxit Reader

> Remote attackers can execute arbitrary code via a malicious PDF file due to improper object validation in Foxit Reader.

- **Severity:** High 8.8 (`CVSS:3.0/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:** No
- **Published:** 17 May 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-pm26-rj28-hv99

## What is CVE-2018-9956?

CVE-2018-9956 is a high-severity use after free vulnerability in Foxitsoftware Foxit Reader, published on 17 May 2018. 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

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.1049. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the handling of XFA Button elements. When setting the title attribute, the process does not properly validate the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-5617.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2018-9956?

It affects 2 products.


Products: Foxitsoftware Foxit Reader, Foxitsoftware Phantompdf.

## How do I fix CVE-2018-9956?

No fix has been published for CVE-2018-9956 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-9956 being exploited?

There is no known exploitation of CVE-2018-9956 in the wild and no public exploit code.

## Other vulnerabilities in Foxitsoftware Foxit Reader

- [CVE-2021-33793](https://insights.sbomify.com/CVE-2021-33793/): Memory corruption in n/a (critical 9.8)
- [CVE-2021-38568](https://insights.sbomify.com/CVE-2021-38568/): Memory corruption in n/a (critical 9.8)
- [CVE-2021-38572](https://insights.sbomify.com/CVE-2021-38572/): Path traversal in n/a (critical 9.8)
- [CVE-2021-38573](https://insights.sbomify.com/CVE-2021-38573/): Path traversal in n/a (critical 9.8)
- [CVE-2021-38574](https://insights.sbomify.com/CVE-2021-38574/): SQL injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-9956 and fix it if it is affected.

What it is: CVE-2018-9956 is a high-severity use after free vulnerability in Foxitsoftware Foxit Reader, published on 17 May 2018. 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-2018-9956 in the wild and no public exploit code.

Affected product: Foxitsoftware Foxit Reader. 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-2018-9956/ (Markdown: https://insights.sbomify.com/CVE-2018-9956/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-9956
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-9956
- OSV: https://osv.dev/vulnerability/CVE-2018-9956

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From sbomify Insights: https://insights.sbomify.com/CVE-2018-9956/
Summaries are generated and may contain mistakes; the official description above is the record.