# CVE-2021-20101: Other in AppNitro Machform

> Attackers can inject HTTP host headers to cause victims to receive malformed content in Machform.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **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:** No
- **Published:** 29 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-83r5-mv86-2rcp

## What is CVE-2021-20101?

CVE-2021-20101 is a medium-severity vulnerability in AppNitro Machform, published on 29 Jun 2021. 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

Machform prior to version 16 is vulnerable to HTTP host header injection due to improperly validated host headers. This could cause a victim to receive malformed content.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2021-20101?

It affects 1 product.


Products: Machform Machform.

## How do I fix CVE-2021-20101?

No fix has been published for CVE-2021-20101 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20101 being exploited?

There is no known exploitation of CVE-2021-20101 in the wild and no public exploit code.

## Other vulnerabilities in AppNitro Machform

- [CVE-2024-37762](https://insights.sbomify.com/CVE-2024-37762/): File upload in n/a (critical 9.9)
- [CVE-2018-6410](https://insights.sbomify.com/CVE-2018-6410/): SQL injection in n/a (critical 9.8)
- [CVE-2018-6411](https://insights.sbomify.com/CVE-2018-6411/): SQL injection in n/a (critical 9.8)
- [CVE-2024-37765](https://insights.sbomify.com/CVE-2024-37765/): SQL injection in n/a (high 8.8)
- [CVE-2021-20102](https://insights.sbomify.com/CVE-2021-20102/): Cross-site request forgery in AppNitro Machform (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20101 and fix it if it is affected.

What it is: CVE-2021-20101 is a medium-severity vulnerability in AppNitro Machform, published on 29 Jun 2021. 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-2021-20101 in the wild and no public exploit code.

Affected product: AppNitro Machform. 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-2021-20101/ (Markdown: https://insights.sbomify.com/CVE-2021-20101/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20101
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20101
- OSV: https://osv.dev/vulnerability/CVE-2021-20101

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20101/
Summaries are generated and may contain mistakes; the official description above is the record.