# CVE-2020-36941: Knockpy 4.1.1 - CSV Injection

> Attackers can inject malicious formulas into CSV reports via unfiltered server headers, leading to code execution when the file is opened in spreadsheet software.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA: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:** 27 Jan 2026
- **Updated:** 5 Mar 2026
- **Also known as:** GHSA-x2h4-97pf-v2rr

## What is CVE-2020-36941?

CVE-2020-36941 is a medium-severity code injection vulnerability in guelfoweb knock, published on 27 Jan 2026. 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

Knockpy 4.1.1 contains a CSV injection vulnerability that allows attackers to inject malicious formulas into CSV reports through unfiltered server headers. Attackers can manipulate server response headers to include spreadsheet formulas that will execute when the CSV is opened in spreadsheet applications.

Weakness: CWE-1236 (Improper Neutralization of Formula Elements in a CSV File)

## Which versions are affected by CVE-2020-36941?

It affects 1 product.


Products: Guelfoweb Knockpy.

## How do I fix CVE-2020-36941?

No fix has been published for CVE-2020-36941 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-36941 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-36941 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-36941 and fix it if it is affected.

What it is: CVE-2020-36941 is a medium-severity code injection vulnerability in guelfoweb knock, published on 27 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-36941 exists.

Affected product: guelfoweb knock. 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-2020-36941/ (Markdown: https://insights.sbomify.com/CVE-2020-36941/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-36941
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-36941
- OSV: https://osv.dev/vulnerability/CVE-2020-36941

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-36941/
Summaries are generated and may contain mistakes; the official description above is the record.