# CVE-2019-20821: Null dereference in n/a

> A NULL pointer dereference in Foxit PhantomPDF for Mac allows attackers to cause a denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Jun 2020
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-wj7w-23cp-3j83

## What is CVE-2019-20821?

CVE-2019-20821 is a high-severity vulnerability in Foxitsoftware Phantompdf, published on 4 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Foxit PhantomPDF Mac before 3.4. It has a NULL pointer dereference.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2019-20821?

It affects 1 product.


Products: Foxitsoftware Phantompdf.

## How do I fix CVE-2019-20821?

No fix has been published for CVE-2019-20821 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-20821 being exploited?

There is no known exploitation of CVE-2019-20821 in the wild and no public exploit code.

## Other vulnerabilities in Foxitsoftware Phantompdf

- [CVE-2018-21242](https://insights.sbomify.com/CVE-2018-21242/): An issue was discovered in Foxit PhantomPDF before 8.3.6. (critical 9.8)
- [CVE-2018-21244](https://insights.sbomify.com/CVE-2018-21244/): File upload in n/a (critical 9.8)
- [CVE-2019-20825](https://insights.sbomify.com/CVE-2019-20825/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-20827](https://insights.sbomify.com/CVE-2019-20827/): Denial of service in n/a (critical 9.8)
- [CVE-2019-20830](https://insights.sbomify.com/CVE-2019-20830/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-20821 and fix it if it is affected.

What it is: CVE-2019-20821 is a high-severity vulnerability in Foxitsoftware Phantompdf, published on 4 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-20821 in the wild and no public exploit code.

Affected product: Foxitsoftware Phantompdf. 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-2019-20821/ (Markdown: https://insights.sbomify.com/CVE-2019-20821/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-20821
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-20821
- OSV: https://osv.dev/vulnerability/CVE-2019-20821

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-20821/
Summaries are generated and may contain mistakes; the official description above is the record.