CVE intelligence and bounded remediation

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

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 access.

Severity
Medium
CVSS
5.5 (3.1)
Published
2020-11-29
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-306

Affected products

  • vsolcn / v1600d4l_firmware / 1.01.49
  • vsolcn / v1600d-mini_firmware / 1.01.48

Matched remediation archetype

Authentication bypass and missing authentication

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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