# CVE-2020-27756: Denial of service in ImageMagick

> A crafted image file can cause a divide-by-zero error in ImageMagick, leading to application crashes and denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/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:** 8 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-27756, GHSA-ghpq-hg85-4p3m, JLSEC-2026-854, UBUNTU-CVE-2020-27756

## What is CVE-2020-27756?

CVE-2020-27756 is a medium-severity denial of service vulnerability in Imagemagick Imagemagick, published on 8 Dec 2020. 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

In ParseMetaGeometry() of MagickCore/geometry.c, image height and width calculations can lead to divide-by-zero conditions which also lead to undefined behavior. This flaw can be triggered by a crafted input file processed by ImageMagick and could impact application availability. The patch uses multiplication in addition to the function `PerceptibleReciprocal()` in order to prevent such divide-by-zero conditions. This flaw affects ImageMagick versions prior to 7.0.9-0.

Weakness: CWE-369 (Divide By Zero)

## Which versions are affected by CVE-2020-27756?

It affects 1 product.


Products: Imagemagick Imagemagick.

## How do I fix CVE-2020-27756?

Upgrade to a fixed version.

## Is CVE-2020-27756 being exploited?

There is no known exploitation of CVE-2020-27756 in the wild and no public exploit code.

## Other vulnerabilities in Imagemagick Imagemagick

- [CVE-2019-19952](https://insights.sbomify.com/CVE-2019-19952/): Use after free in n/a (critical 9.8)
- [CVE-2018-16328](https://insights.sbomify.com/CVE-2018-16328/): Null dereference in n/a (critical 9.8)
- [CVE-2018-16329](https://insights.sbomify.com/CVE-2018-16329/): Null dereference in n/a (critical 9.8)
- [CVE-2017-18210](https://insights.sbomify.com/CVE-2017-18210/): Null dereference in n/a (critical 9.8)
- [CVE-2017-14138](https://insights.sbomify.com/CVE-2017-14138/): Denial of service in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-27756 and fix it if it is affected.

What it is: CVE-2020-27756 is a medium-severity denial of service vulnerability in Imagemagick Imagemagick, published on 8 Dec 2020. 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-2020-27756 in the wild and no public exploit code.

Affected product: Imagemagick Imagemagick. 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-2020-27756/ (Markdown: https://insights.sbomify.com/CVE-2020-27756/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-27756
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-27756
- OSV: https://osv.dev/vulnerability/CVE-2020-27756

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-27756/
Summaries are generated and may contain mistakes; the official description above is the record.