# CVE-2018-20662: Denial of service in n/a

> Attackers can cause a denial-of-service crash in Poppler by crafting a malicious PDF file with a malformed xref structure.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 3 Jan 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-20662, GHSA-mwx3-cc72-hfg4, SUSE-SU-2023:4690-1, SUSE-SU-2023:4942-1, UBUNTU-CVE-2018-20662

## What is CVE-2018-20662?

CVE-2018-20662 is a medium-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 3 Jan 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

In Poppler 0.72.0, PDFDoc::setup in PDFDoc.cc allows attackers to cause a denial-of-service (application crash caused by Object.h SIGABRT, because of a wrong return value from PDFDoc::setup) by crafting a PDF file in which an xref data structure is mishandled during extractPDFSubtype processing.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2018-20662?

It affects 11 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `poppler` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 0.43.0-16.43.1 |
| `poppler-qt` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 0.43.0-16.43.1 |
| `poppler` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 0.43.0-16.43.1 |
| `poppler-qt` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 0.43.0-16.43.1 |
| `poppler` | SUSE:Linux Enterprise Software Development Kit 12 SP5 | All versions | 0.43.0-16.43.1 |
| `poppler-qt` | SUSE:Linux Enterprise Software Development Kit 12 SP5 | All versions | 0.43.0-16.43.1 |
| `poppler` | openSUSE:Leap 15.4 | All versions | 0.62.0-150000.4.34.1 |

Products: Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Freedesktop Poppler, Redhat Enterprise Linux, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Tus, Redhat Enterprise Linux Workstation.

## How do I fix CVE-2018-20662?

Apply the vendor's patch.

## Is CVE-2018-20662 being exploited?

There is no known exploitation of CVE-2018-20662 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20662 and fix it if it is affected.

What it is: CVE-2018-20662 is a medium-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 3 Jan 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-2018-20662 in the wild and no public exploit code.

Affected product: Canonical Ubuntu Linux. 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-2018-20662/ (Markdown: https://insights.sbomify.com/CVE-2018-20662/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20662
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20662
- OSV: https://osv.dev/vulnerability/CVE-2018-20662

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20662/
Summaries are generated and may contain mistakes; the official description above is the record.