# CVE-2021-20745: Command injection in Inkdrop

> Attackers can execute arbitrary OS commands on the host system by tricking users into loading malicious content in Inkdrop.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 28 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-fgmm-f4rh-2m84

## What is CVE-2021-20745?

CVE-2021-20745 is a high-severity command injection vulnerability in Takuya Matsuyama Inkdrop, published on 28 Jun 2021. 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

Inkdrop versions prior to v5.3.1 allows an attacker to execute arbitrary OS commands on the system where it runs by loading a file or code snippet containing an invalid iframe into Inkdrop.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2021-20745?

It affects 1 product.


Products: Inkdrop Inkdrop.

## How do I fix CVE-2021-20745?

No fix has been published for CVE-2021-20745 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20745 being exploited?

There is no known exploitation of CVE-2021-20745 in the wild and no public exploit code.

## Other vulnerabilities in Takuya Matsuyama Inkdrop

- [CVE-2023-44141](https://insights.sbomify.com/CVE-2023-44141/): Code injection in Inkdrop (high 7.8)
- [CVE-2022-46603](https://insights.sbomify.com/CVE-2022-46603/): Code injection in n/a (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20745 and fix it if it is affected.

What it is: CVE-2021-20745 is a high-severity command injection vulnerability in Takuya Matsuyama Inkdrop, published on 28 Jun 2021. 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-2021-20745 in the wild and no public exploit code.

Affected product: Takuya Matsuyama Inkdrop. 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-2021-20745/ (Markdown: https://insights.sbomify.com/CVE-2021-20745/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20745
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20745
- OSV: https://osv.dev/vulnerability/CVE-2021-20745

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20745/
Summaries are generated and may contain mistakes; the official description above is the record.