# CVE-2018-20751: Null dereference in n/a

> A crafted PDF document triggers a NULL pointer dereference in PoDoFo, causing a denial of service.

- **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:** Yes
- **Published:** 4 Feb 2019
- **Updated:** 17 Sep 2024
- **Also known as:** DEBIAN-CVE-2018-20751, GHSA-crhg-hr6g-j2xf, UBUNTU-CVE-2018-20751

## What is CVE-2018-20751?

CVE-2018-20751 is a high-severity vulnerability in Podofo Project Podofo, published on 4 Feb 2019. 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

An issue was discovered in crop_page in PoDoFo 0.9.6. For a crafted PDF document, pPage->GetObject()->GetDictionary().AddKey(PdfName("MediaBox"),var) can be problematic due to the function GetObject() being called for the pPage NULL pointer object. The value of pPage at this point is 0x0, which causes a NULL pointer dereference.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2018-20751?

It affects 1 product.


Products: Podofo Project Podofo.

## How do I fix CVE-2018-20751?

Upgrade to a fixed version.

## Is CVE-2018-20751 being exploited?

There is no known exploitation of CVE-2018-20751 in the wild and no public exploit code.

## Other vulnerabilities in Podofo Project Podofo

- [CVE-2017-8378](https://insights.sbomify.com/CVE-2017-8378/): Memory corruption in n/a (critical 9.8)
- [CVE-2015-8981](https://insights.sbomify.com/CVE-2015-8981/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-31556](https://insights.sbomify.com/CVE-2023-31556/): Memory corruption in n/a (high 8.8)
- [CVE-2023-31566](https://insights.sbomify.com/CVE-2023-31566/): Use after free in n/a (high 8.8)
- [CVE-2023-31567](https://insights.sbomify.com/CVE-2023-31567/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20751 and fix it if it is affected.

What it is: CVE-2018-20751 is a high-severity vulnerability in Podofo Project Podofo, published on 4 Feb 2019. 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-2018-20751 in the wild and no public exploit code.

Affected product: Podofo Project Podofo. 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-2018-20751/ (Markdown: https://insights.sbomify.com/CVE-2018-20751/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20751
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20751
- OSV: https://osv.dev/vulnerability/CVE-2018-20751

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20751/
Summaries are generated and may contain mistakes; the official description above is the record.