# CVE-2020-27818: Denial of service in pngcheck

> An attacker can cause a temporary denial of service in pngcheck by providing a malicious file, affecting application availability.

- **Severity:** Low 3.3 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L`)
- **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-2020-27818, DLA-3032-1, GHSA-xjm9-9gr6-gcpx, UBUNTU-CVE-2020-27818, openSUSE-SU-2020:2177-1, openSUSE-SU-2020:2198-1, openSUSE-SU-2020:2220-1, openSUSE-SU-2020:2227-1, openSUSE-SU-2024:11176-1

## What is CVE-2020-27818?

CVE-2020-27818 is a low-severity denial of service vulnerability in Debian Debian Linux, 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

A flaw was found in the check_chunk_name() function of pngcheck-2.4.0. An attacker able to pass a malicious file to be processed by pngcheck could cause a temporary denial of service, posing a low risk to application availability.

Weakness: CWE-125 (Out-of-bounds Read), CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2020-27818?

It affects 4 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pngcheck` | SUSE:Package Hub 15 SP1 | All versions | 2.3.0-bp151.4.3.1 |
| `pngcheck` | SUSE:Package Hub 15 SP2 | All versions | 2.3.0-bp152.4.3.1 |
| `pngcheck` | openSUSE:Leap 15.1 | All versions | 2.3.0-lp151.3.3.1 |
| `pngcheck` | openSUSE:Leap 15.2 | All versions | 2.3.0-lp152.4.3.1 |
| `pngcheck` | openSUSE:Tumbleweed | All versions | 3.0.0-1.7 |

Products: Debian Debian Linux, Fedoraproject Extra Packages for Enterprise Linux, Fedoraproject Fedora, Libpng Pngcheck.

## How do I fix CVE-2020-27818?

Apply the vendor's patch.

## Is CVE-2020-27818 being exploited?

There is no known exploitation of CVE-2020-27818 in the wild and no public exploit code.

Public exploit code:

- A repository of proof-of-concept files demonstrating disclosed and patched vulnerabilities in pngcheck (2.4.0 - 3.0.1), including CVE-2020-27818, CVE-2020-35511 and other vulns. (github_poc): https://github.com/13m0n4de/pngcheck-vulns

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-27818 and fix it if it is affected.

What it is: CVE-2020-27818 is a low-severity denial of service vulnerability in Debian Debian Linux, 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-2020-27818 in the wild and no public exploit code.

Affected product: Debian Debian 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-2020-27818/ (Markdown: https://insights.sbomify.com/CVE-2020-27818/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-27818
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-27818
- OSV: https://osv.dev/vulnerability/CVE-2020-27818

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-27818/
Summaries are generated and may contain mistakes; the official description above is the record.