Knockpy 4.1.1 contains a CSV injection vulnerability that allows attackers to inject malicious formulas into CSV reports through unfiltered server hea...
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.
AI Analyst Comment
Remediation
Update Knockpy Multiple Products to the latest version. Check vendor security advisory for specific patch details. Monitor for exploitation attempts and review access logs.
---METADATA---
VENDOR: guelfoweb
PRODUCT: knock
AFFECTED_VERSIONS: 4.1.1
CONFIDENCE: high
MISSING: patch
---END_METADATA---
Description Summary:
Knockpy 4.1.1 contains a CSV injection vulnerability where malicious server headers can be used to inject formulas into reports, which execute when opened in spreadsheet software.
Executive Summary:
A CSV injection vulnerability in Knockpy 4.1.1 could allow attackers to execute malicious formulas by manipulating server headers captured in scan reports.
Vulnerability Details
CVE-ID: CVE-2020-36941
Affected Software: guelfoweb knock
Affected Versions: 4.1.1
Vulnerability: This is a CWE-1236 Improper Neutralization of Formula Elements vulnerability. An unauthenticated attacker can influence server headers, which are subsequently written into CSV reports without adequate sanitization, leading to formula execution.
Business Impact
Successful exploitation poses a risk to the security of the analyst's workstation or any system used to review the generated scan reports. If an attacker successfully injects a malicious formula, they could potentially trigger unauthorized commands or exfiltrate local data when the CSV file is opened, impacting the confidentiality and integrity of the user's environment.
Remediation Plan
Immediate Action: Upgrade to the latest version of the knockpy tool, as the maintainers have implemented necessary sanitization to prevent formula injection.
Proactive Monitoring: Inspect scan reports for suspicious formulaic content in the header fields if immediate patching is not feasible.
Compensating Controls: Utilize security settings in spreadsheet applications to prompt for confirmation before executing external data links or formulas in CSV files.
Exploitation Status
Public Exploit Available: Yes — an entry exists on ExploitDB (49342).
Analyst Notes: As of Jan 27, 2026, there is no confirmed active exploitation in the wild; however, per CISA's SSVC assessment a proof-of-concept exists, so exploitation risk should be treated as credible. The vulnerability is highly accessible to attackers who can influence the target server's response headers.
Analyst Recommendation
Organizations using Knockpy 4.1.1 must update to the latest release to eliminate this vulnerability. Until updates are applied, analysts should treat generated CSV files as untrusted and exercise caution when opening them in spreadsheet software.