CVE-2018-20391: TEKNOTEL CBW700N 81.447.392110.729.024 devices allow remote attackers to discover credentials via iso.3.6.1.4.

This week

CRITICAL 9.8REMOTEMITIGATE

CVE-2018-20391 is a critical-severity flaw (CVSS 9.8) affecting cbw700n firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

TEKNOTEL CBW700N 81.447.392110.729.024 devices allow remote attackers to discover credentials via iso.3.6.1.4.1.4491.2.4.1.1.6.1.1.0 and iso.3.6.1.4.1.4491.2.4.1.1.6.1.2.0 SNMP requests.

Why this priority

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

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-522
Published	2018-12-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: teknotel

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

Am I affected?

Timeline

2018-12-23 21:29 UTCPublished CVE record published
2026-06-17 01:52 UTCUpdated Record last modified

teknotel cbw700n firmware MITIGATE

Affected: 81.447.392110.729.024

Fixed in: no fixed release known

Safe to downgrade to: a release before 81.447.392110.729.024

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-2018-20391?

cbw700n firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-20391 being exploited?

CVE-2018-20391 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-2018-20391 affect?

CVE-2018-20391 affects cbw700n firmware. Severity is critical (CVSS 9.8). TEKNOTEL CBW700N 81.447.392110.729.024 devices allow remote attackers to discover credentials via iso.3.6.1.4.1.4491.2.4.1.1.6.1.1.0 and iso.3.6.1.4.1.4491.2.4.1.1.6.1.2.0 SNMP requests.

How urgent is CVE-2018-20391?

Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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