CVE-2021-25909: ZIV Automation 4CCT-EA6-334126BF firmware version 3.23.80.27.36371, allows an unauthenticated, remote attacker

This month

HIGH 8.6REMOTEMITIGATE

CVE-2021-25909 is a high-severity flaw (CVSS 8.6) affecting 4cct-ea6-334126bf firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ZIV Automation 4CCT-EA6-334126BF firmware version 3.23.80.27.36371, allows an unauthenticated, remote attacker to cause a denial of service condition on the device. An attacker could exploit this vulnerability by sending specific packets to the port 7919.

Why this priority

High severity
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	8.6 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Weakness	CWE-400
Published	2021-01-29
Last modified	2026-06-17

Publisher (CNA): Spanish National Cybersecurity Institute, S.A. (INCIBE) · Vendor: zivautomation

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

Am I affected?

Timeline

2021-01-29 14:15 UTCPublished CVE record published
2026-06-17 03:42 UTCUpdated Record last modified

zivautomation 4cct-ea6-334126bf firmware MITIGATE

Affected: 3.23.80.27.36371

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.23.80.27.36371

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-2021-25909?

4cct-ea6-334126bf firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-25909 being exploited?

CVE-2021-25909 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-2021-25909 affect?

CVE-2021-25909 affects 4cct-ea6-334126bf firmware. Severity is high (CVSS 8.6). ZIV Automation 4CCT-EA6-334126BF firmware version 3.23.80.27.36371, allows an unauthenticated, remote attacker to cause a denial of service condition on the device. An attacker could exploit this vulnerability by sending specific packets to

How urgent is CVE-2021-25909?

Priority 53/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-25910 HIGH 8.0 MITIGATE Improper Authentication vulnerability in the cookie parameter of ZIV AUTOMATION 4CCT-EA6-334126BF allows a loc

References

← Back to latest CVEs