CVE-2020-29379: An issue was discovered on V-SOL V1600D4L V1.01.49 and V1600D-MINI V1.01.48 OLT devices

Routine

MEDIUM 5.5MITIGATEMITIGATE

CVE-2020-29379 is a medium-severity flaw (CVSS 5.5) affecting v1600d4l firmware, v1600d-mini firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered on V-SOL V1600D4L V1.01.49 and V1600D-MINI V1.01.48 OLT devices. During the process of updating the firmware, the update script starts a telnetd -l /bin/sh process that does not require authentication for TELNET access.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 75%)
CISA exploited list	No
Weakness	CWE-306
Published	2020-11-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: vsolcn

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

Am I affected?

Timeline

2020-11-29 01:15 UTCPublished CVE record published
2026-06-17 03:11 UTCUpdated Record last modified

vsolcn v1600d4l firmware MITIGATE

Affected: 1.01.49

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.01.49

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.

vsolcn v1600d-mini firmware MITIGATE

Affected: 1.01.48

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.01.48

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-2020-29379?

v1600d4l firmware: mitigate or apply the listed mitigation; v1600d-mini firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-29379 being exploited?

CVE-2020-29379 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-2020-29379 affect?

CVE-2020-29379 affects v1600d4l firmware, v1600d-mini firmware. Severity is medium (CVSS 5.5). An issue was discovered on V-SOL V1600D4L V1.01.49 and V1600D-MINI V1.01.48 OLT devices. During the process of updating the firmware, the update script starts a telnetd -l /bin/sh process that does not require authentication for TELNET acce

How urgent is CVE-2020-29379?

Priority 31/100. Public exploit reference

Related CVEs

CVE-2020-29383 HIGH 7.8 MITIGATE MITIGATE An issue was discovered on V-SOL V1600D4L V1.01.49 and V1600D-MINI V1.01.48 OLT devices
CVE-2020-29381 CRITICAL 9.8 MITIGATE MITIGATE An issue was discovered on V-SOL V1600D V2.03.69 and V2.03.57, V1600D4L V1.01.49, V1600D-MINI V1.01.48, V1600G
CVE-2020-29380 MEDIUM 5.9 MITIGATE MITIGATE An issue was discovered on V-SOL V1600D V2.03.69 and V2.03.57, V1600D4L V1.01.49, V1600D-MINI V1.01.48, V1600G
CVE-2020-29378 HIGH 8.8 MITIGATE MITIGATE An issue was discovered on V-SOL V1600D V2.03.69 and V2.03.57, V1600D4L V1.01.49, V1600D-MINI V1.01.48, V1600G
CVE-2020-29376 CRITICAL 9.8 MITIGATE MITIGATE An issue was discovered on V-SOL V1600D V2.03.69 and V2.03.57, V1600D4L V1.01.49, V1600D-MINI V1.01.48, V1600G

References

← Back to latest CVEs