CVE-2021-41738: ZeroShell 3.9.5 has a command injection vulnerability in /cgi-bin/kerbynet IP parameter, which may allow an au

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HIGH 8.8MITIGATE

CVE-2021-41738 is a high-severity flaw (CVSS 8.8) affecting zeroshell. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ZeroShell 3.9.5 has a command injection vulnerability in /cgi-bin/kerbynet IP parameter, which may allow an authenticated attacker to execute system commands.

Why this priority

High severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.8% (top 21%)
CISA exploited list	No
Weakness	CWE-78
Published	2022-06-11
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: zeroshell

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

Am I affected?

Timeline

2022-06-11 14:15 UTCPublished CVE record published
2026-06-17 04:08 UTCUpdated Record last modified

zeroshell zeroshell MITIGATE

Affected: 3.9.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.9.5

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2021-41738?

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

Is CVE-2021-41738 being exploited?

CVE-2021-41738 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-2021-41738 affect?

CVE-2021-41738 affects zeroshell. Severity is high (CVSS 8.8). ZeroShell 3.9.5 has a command injection vulnerability in /cgi-bin/kerbynet IP parameter, which may allow an authenticated attacker to execute system commands.

How urgent is CVE-2021-41738?

Priority 50/100. High severity

Related CVEs

CVE-2020-29390 CRITICAL 9.8 MITIGATE Zeroshell 3.9.3 contains a command injection vulnerability in the /cgi-bin/kerbynet StartSessionSubmit paramet

References

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