CSV Injection Vulnerability in Knockpy by GuelfoWeb
CVE-2020-36941

5.3MEDIUM

Key Information:

Vendor

Guelfoweb

Status
Knock
Vendor
CVE Published:
27 January 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2020-36941?

Knockpy 4.1.1 possesses a vulnerability that allows attackers to execute malicious formulas through crafted server headers in CSV reports. By manipulating the server response headers, an attacker can inject harmful formulas that trigger automatically when the CSV file is opened in a spreadsheet application, posing a significant risk to users who may unknowingly execute the embedded code.

Affected Version(s)

knock 4.1.1

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2020-36941 - Proof of Concept

References

https://www.exploit-db.com/exploits/49342
exploit
https://github.com/guelfoweb/knock
product
https://www.vulncheck.com/advisories/knockpy-csv-injection
third-party-advisory

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Dolev Farhi
.