# CVE-2018-6544: Denial of service in n/a

> Remote attackers can cause a denial of service in MuPDF via a crafted PDF document triggering recursive object stream references.

- **Severity:** Medium 5.5 (`CVSS:3.0/AV:L/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:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 2 Feb 2018
- **Updated:** 5 Aug 2024
- **Also known as:** ALPINE-CVE-2018-6544, DEBIAN-CVE-2018-6544, GHSA-3vq6-g92c-jm9j, UBUNTU-CVE-2018-6544

## What is CVE-2018-6544?

CVE-2018-6544 is a medium-severity denial of service vulnerability in Artifex Mupdf, published on 2 Feb 2018. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

pdf_load_obj_stm in pdf/pdf-xref.c in Artifex MuPDF 1.12.0 could reference the object stream recursively and therefore run out of error stack, which allows remote attackers to cause a denial of service via a crafted PDF document.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2018-6544?

It affects 2 products.


Products: Artifex Mupdf, Debian Debian Linux.

## How do I fix CVE-2018-6544?

Upgrade to a fixed version.

## Is CVE-2018-6544 being exploited?

There is no known exploitation of CVE-2018-6544 in the wild and no public exploit code.

## Other vulnerabilities in Artifex Mupdf

- [CVE-2019-7321](https://insights.sbomify.com/CVE-2019-7321/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-6525](https://insights.sbomify.com/CVE-2016-6525/): Memory corruption in n/a (critical 9.8)
- [CVE-2011-0341](https://insights.sbomify.com/CVE-2011-0341/): Memory corruption in n/a (critical 9.3)
- [CVE-2016-8728](https://insights.sbomify.com/CVE-2016-8728/): Memory corruption in MuPDF (high 8.6)
- [CVE-2021-3407](https://insights.sbomify.com/CVE-2021-3407/): Use after free in mupdf (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-6544 and fix it if it is affected.

What it is: CVE-2018-6544 is a medium-severity denial of service vulnerability in Artifex Mupdf, published on 2 Feb 2018. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-6544 in the wild and no public exploit code.

Affected product: Artifex Mupdf. 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-2018-6544/ (Markdown: https://insights.sbomify.com/CVE-2018-6544/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-6544
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-6544
- OSV: https://osv.dev/vulnerability/CVE-2018-6544

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-6544/
Summaries are generated and may contain mistakes; the official description above is the record.