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A7100Ru CVE-2026-5978

| EUVDEUVD-2026-21185 HIGH
OS Command Injection (CWE-78)
2026-04-09 VulDB GHSA-gpqj-8899-c755
8.9
CVSS 4.0 · Vendor: VulDB
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Send HTTP request to /cgi-bin/cstecgi.cgi
  2. Exploit
    Inject OS commands in mode parameter
  3. Execution
    Execute arbitrary commands on router
  4. Impact
    Achieve remote code execution

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.

Exploitation Conditions

Remote unauthenticated attacker can exploit the setWiFiAclRules function in /cgi-bin/cstecgi.cgi on Totolink A7100RU firmware version 7.4cu.2313_b20191024 by injecting OS commands via the mode parameter. No authentication or user interaction required.

Impact

High-severity unauthenticated remote command injection in Totolink router CGI handler. CVSS 8.9 reflects complete system compromise (high confidentiality, integrity, availability impact). Network-accessible attack surface, minimal complexity, and public exploit code create immediate risk for unpatched devices. Widely deployed consumer routers amplify blast radius.

Exploit ScenarioDerived

Attacker sends HTTP request to /cgi-bin/cstecgi.cgi with malicious OS command injected into 'mode' parameter of setWiFiAclRules function. No authentication required. Publicly available exploit code enables rapid weaponization against vulnerable router instances.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.9% exploitation probability (EPSS)

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AnalysisAIv1 – Apr 09, 2026

OS command injection in Totolink A7100RU router firmware 7.4cu.2313_b20191024 allows unauthenticated remote attackers to execute arbitrary system commands via the 'mode' parameter in the setWiFiAclRules function (/cgi-bin/cstecgi.cgi). Publicly available exploit code exists. Attackers can achieve complete device compromise with high impact to confidentiality, integrity, and availability of the router. No authentication required for exploitation (CVSS PR:N).

RemediationAI

No vendor-released patch identified at time of analysis. Totolink has not published security advisories or firmware updates addressing this vulnerability per vendor website (https://www.totolink.net/). Recommended immediate actions: disable remote administration interfaces (web UI, CGI access) from WAN-facing networks; restrict management access to trusted internal IP ranges only via firewall rules; monitor for unauthorized configuration changes in WiFi ACL settings. Consider device replacement if vendor does not release patched firmware within acceptable risk timeframe. Reference exploit details: https://github.com/Litengzheng/vuldb_new/blob/main/A7100RU/vul_164/README.md. Vendor contact: https://www.totolink.net/. VulDB advisory: https://vuldb.com/vuln/356532.

Affected VersionsENISA

A7100RU 7.4cu.2313_b20191024

Affected Packages

euvd a7100ru no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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

Technical ContextAI · show details

CWE-78 OS command injection in CGI handler. The setWiFiAclRules function fails to sanitize the 'mode' argument before passing it to shell execution context. Attacker-controlled input is directly interpolated into system calls, enabling arbitrary command execution with router process privileges. Network-accessible CGI endpoint exposes vulnerability without authentication boundary.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulDB) PRIMARY 8.9 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

Primary rating from Vendor (VulDB) · only source for this CVE.

CVSS VectorVendor: VulDB

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

2
PoC Detected
Apr 09, 2026 - 21:16 vuln.today
Public exploit code
CVE Published
Apr 09, 2026 - 20:30 nvd
HIGH 8.9

DescriptionCVE.org

A security vulnerability has been detected in Totolink A7100RU 7.4cu.2313_b20191024. Affected is the function setWiFiAclRules of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. The manipulation of the argument mode leads to os command injection. The attack can be initiated remotely. The exploit has been disclosed publicly and may be used.

Executive ViewAI

Why It Matters

Totolink A7100RU routers running firmware 7.4cu.2313_b20191024 contain a critical unauthenticated remote code execution vulnerability (CVE-2026-5978) that allows attackers to seize complete control of affected devices without credentials. Organizations deploying this router model face immediate risk of network compromise, data interception, and lateral movement into connected systems, with publicly available exploit code accelerating attack likelihood.

Business Impact: Severe
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: (1) Restrict WAN-to-router access via network firewall rules blocking external connectivity to /cgi-bin/cstecgi.cgi; (2) Implement network segmentation isolating router management functions; (3) Deploy intrusion detection signatures for mode parameter exploitation attempts; (4) Monitor router logs for suspicious cgi.cgi access patterns; (5) Disable remote management features if operationally feasible; (6) Consider replacement with patched alternative router model pending vendor patch release.

Threat Intelligence Overview

EPSS Score
0.9%
Top 24% exploitable
Exploit
POC
Public exploit code exists
Data Quality
7 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment GitHub VulDB

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 HIGH
CISA KEV No
Public POC Yes
EPSS 0.9%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Out-of-Cycle
Exploitation
Poc
System Exposure· derived
Open
Automatable
Yes
Human Impact
Very High
Technical Impact
Total

Priority Score

65
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +44
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.

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