CVE-2021-27171Public exploitNetwork attack vector

Root shell access via debug CLI commands

Published Feb 10, 2021 · Updated Aug 3, 2024

Privilege escalation in FiberHome HG6245D through RP2613 allows remote authenticated users to start a root telnet service. The CLI's ddd debug context exposes shell and tshell commands that call enter_telnet_shell(), which invokes system("telnet -p 26") as root. Access to the CLI on port 23 is required; the resulting service on port 26 accepts the device's hardcoded root credentials and grants a root shell.

CVSS severity9.8
Critical
EPSS probability17.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Privilege escalation in FiberHome HG6245D through RP2613 allows remote authenticated users to start a root telnet service. The CLI's ddd debug context exposes shell and tshell commands that call enter_telnet_shell(), which invokes system("telnet -p 26") as root. Access to the CLI on port 23 is required; the resulting service on port 26 accepts the device's hardcoded root credentials and grants a root shell.

The record

CVE
CVE-2021-27171
Published
Feb 10, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1059.008, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1059.008Command and Scripting Interpreter: Network Device CLI
T1059.004Command and Scripting Interpreter: Unix Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo