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X5000r Firmware CVE-2021-27710

CRITICAL
OS Command Injection (CWE-78)
2021-04-14 cve@mitre.org
9.8
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization OS command sanitization, avoid shell exec
MITRE ATT&CK

2 techniques across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A remote attacker could execute arbitrary operating system commands on the host by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.
No patch listed yet 7.9% exploitation probability (EPSS)

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AnalysisAI

Command Injection in TOTOLINK X5000R router with firmware v9.1.0u.6118_B20201102, and TOTOLINK A720R router with firmware v4.1.5cu.470_B20200911 allows remote attackers to execute arbitrary OS. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Avoid passing user input to shell commands. Use language-specific APIs instead of shell execution. Apply strict input validation with allowlists.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as OS Command Injection (CWE-78), which allows attackers to execute arbitrary operating system commands on the host. Command Injection in TOTOLINK X5000R router with firmware v9.1.0u.6118_B20201102, and TOTOLINK A720R router with firmware v4.1.5cu.470_B20200911 allows remote attackers to execute arbitrary OS commands by sending a modified HTTP request. This occurs because the function executes glibc's system function with untrusted input. In the function, "ip" parameter is directly passed to the attacker, allowing them to control the "ip" field to attack the OS. Affected products include: Totolink X5000R Firmware, Totolink A720R Firmware.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionNVD

Command Injection in TOTOLINK X5000R router with firmware v9.1.0u.6118_B20201102, and TOTOLINK A720R router with firmware v4.1.5cu.470_B20200911 allows remote attackers to execute arbitrary OS commands by sending a modified HTTP request. This occurs because the function executes glibc's system function with untrusted input. In the function, "ip" parameter is directly passed to the attacker, allowing them to control the "ip" field to attack the OS.

Threat Intelligence Overview

EPSS Score
7.9%
Top 6% exploitable
Exploit
POC
Public exploit code exists
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC Yes
EPSS 7.9%
Patch available No
Active threat No
Deciding rule
CRITICAL severity + public POC available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

77
Low Medium High Critical
KEV: 0
EPSS: +8
CVSS: +49
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

OS command injection occurs when an application passes unsanitized user input directly into system shell commands.

Affected Products (CPE)NVD

cpe:2.3:o:totolink:x5000r_firmware:9.1.0u.6118_b20201102:*:*:*:*:*:*:*
cpe:2.3:o:totolink:a720r_firmware:4.1.5cu.470_b20200911:*:*:*:*:*:*:*
CVE-2023-30013 CRITICAL POC
9.8 May 05

TOTOLINK X5000R V9.1.0u.6118_B20201102 and V9.1.0u.6369_B20230113 contain a command insertion vulnerability in setting/s

CVE-2025-13184 CRITICAL POC
9.8 Dec 10

Unauthenticated remote attackers can enable Telnet on TOTOLINK X5000R AX1800 routers running firmware V9.1.0u.6369_B2023

CVE-2023-31569 CRITICAL POC
9.8 Jun 06

TOTOLINK X5000R V9.1.0cu.2350_B20230313 was discovered to contain a command injection via the setWanCfg function. Rated

CVE-2025-70327 CRITICAL POC
9.8 Feb 23

Argument injection in TOTOLINK X5000R router v9.1.0cu via setDiagnosisCfg handler allows unauthenticated remote code exe

CVE-2024-32353 CRITICAL POC
9.8 May 14

TOTOLINK X5000R V9.1.0cu.2350_B20230313 was discovered to contain a command injection vulnerability via the 'port' param

CVE-2024-28639 CRITICAL POC
9.8 Mar 16

Buffer Overflow vulnerability in TOTOLink X5000R V9.1.0u.6118-B20201102 and A7000R V9.1.0u.6115-B20201022, allow remote

CVE-2023-6612 CRITICAL POC
9.8 Dec 08

A vulnerability was found in Totolink X5000R 9.1.0cu.2300_B20230112. Rated critical severity (CVSS 9.8), this vulnerabil

CVE-2023-45984 CRITICAL POC
9.8 Oct 16

TOTOLINK X5000R V9.1.0u.6118_B20201102 and TOTOLINK A7000R V9.1.0u.6115_B20201022 was discovered to contain a stack over

CVE-2023-36950 CRITICAL POC
9.8 Oct 16

TOTOLINK X5000R V9.1.0u.6118_B20201102 and TOTOLINK A7000R V9.1.0u.6115_B20201022 was discovered to contain a stack over

CVE-2023-36947 CRITICAL POC
9.8 Oct 16

TOTOLINK X5000R V9.1.0u.6118_B20201102 and TOTOLINK A7000R V9.1.0u.6115_B20201022 was discovered to contain a stack over

CVE-2023-39618 CRITICAL POC
9.8 Aug 21

TOTOLINK X5000R B20210419 was discovered to contain a remote code execution (RCE) vulnerability via the setTracerouteCfg

CVE-2023-39617 CRITICAL POC
9.8 Aug 21

TOTOLINK X5000R_V9.1.0cu.2089_B20211224 and X5000R_V9.1.0cu.2350_B20230313 were discovered to contain a remote code exec

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