CVE-2020-36941: Knockpy 4.1.1 contains a CSV injection vulnerability that allows attackers to inject malicious formulas into C

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2020-36941 is a critical-severity flaw (CVSS 9.8) affecting knockpy. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-1236
Published	2026-01-27
Last modified	2026-06-17

Publisher (CNA): VulnCheck · Vendor: guelfoweb

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-01-27 16:16 UTCPublished CVE record published
2026-06-17 03:16 UTCUpdated Record last modified

guelfoweb knockpy DOWNGRADE

Affected: 4.1.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.1.1

1. Check installed version

apt-cache policy knockpy || rpm -q knockpy || knockpy --version

2. No fixed release: DOWNGRADE to a release before 4.1.1 (Debian / Ubuntu)

apt-cache madison knockpy sudo apt install knockpy=<VERSION_BEFORE_4.1.1> sudo apt-mark hold knockpy

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list knockpy sudo dnf downgrade knockpy-<VERSION_BEFORE_4.1.1> sudo dnf versionlock add knockpy

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora ELN · openjpeg · FIXED · 2.5.4-5.eln159 · FEDORA-2026-1a5f60f401 · source

sudo dnf upgrade --advisory=FEDORA-2026-1a5f60f401

Fedora 46 · trustedqsl · FIXED · 2.8.7-1.fc46 · FEDORA-2026-6b1bc90ebc · source

sudo dnf upgrade --advisory=FEDORA-2026-6b1bc90ebc

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: github.com/guelfoweb/knock
Write-up: www.exploit-db.com/exploits/49342

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-36941?

knockpy: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-36941 being exploited?

CVE-2020-36941 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-36941 affect?

CVE-2020-36941 affects knockpy. Severity is critical (CVSS 9.8). 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 tha

How urgent is CVE-2020-36941?

Priority 56/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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