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Sdt Cs3b1 EUVDEUVD-2017-18938

| CVE-2017-20222 HIGH
Missing Authentication for Critical Function (CWE-306)
2026-03-16 VulnCheck
8.7
CVSS 4.0 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication required for critical functions
MITRE ATT&CK

1 technique across 1 tactic: Initial Access

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

Impact

While the CVSS 7.5 score indicates high severity (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), the real-world risk requires nuanced assessment. The attack is network-accessible with low complexity and requires no privileges or user interaction, making it easily exploitable. Multiple public exploits exist (Exploit-DB, PacketStorm Security), significantly increasing risk. However, the impact is limited to availability only - no data breach or system compromise occurs. The vulnerability is not in CISA KEV, suggesting no known active exploitation in the wild. For organizations using these routers, this represents a moderate-to-high priority issue primarily due to the ease of exploitation and potential for automated attacks causing service disruption.

Exploit ScenarioDerived

An attacker identifies a Telesquare SDT-CS3B1 router through network scanning or Shodan searches. Using readily available exploit code from Exploit-DB (43401) or PacketStorm (145555), they send a simple HTTP POST request to http://[router-ip]/lte.cgi with the parameter 'Command=Reboot'. The router immediately restarts without any authentication check, disrupting all connected services. This attack can be automated to repeatedly reboot the device every few minutes, creating persistent denial of service. In a targeted scenario, attackers could time the reboots to coincide with critical business operations or combine with other attacks during the reboot window.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 16, 2026

An unauthenticated remote reboot vulnerability exists in the Telesquare SKT LTE Router SDT-CS3B1 firmware version 1.2.0, allowing attackers to trigger device restarts without any authentication by sending specially crafted POST requests to the lte.cgi endpoint. This vulnerability has a publicly available proof-of-concept exploit and enables denial of service attacks against affected routers. The vulnerability has been assigned a high CVSS score of 7.5 due to the complete availability impact and lack of authentication requirements.

RemediationAI

No patch information or updated firmware version is mentioned in any of the provided references. Primary mitigation involves restricting network access to the router's management interface through firewall rules or access control lists. Organizations should: 1) Limit access to the lte.cgi endpoint to trusted IP addresses only, 2) Place the router management interface on a separate management VLAN, 3) Contact Telesquare for firmware updates addressing this vulnerability, 4) Monitor for unusual reboot patterns that could indicate exploitation attempts. The VulnCheck advisory (https://www.vulncheck.com/advisories/telesquare-skt-lte-router-sdt-cs3b1-unauthenticated-remote-reboot) may contain additional vendor-specific guidance.

Affected VersionsENISA

SDT-CS3B1 1.2.0

Affected Packages

euvd sdt_cs3b1 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

The vulnerability affects the Telesquare SKT LTE Router model SDT-CS3B1 running firmware version 1.2.0, as identified by CPE string cpe:2.3:a:telesquare:sdt-cs3b1:*:*:*:*:*:*:*:*. The root cause is CWE-306 (Missing Authentication for Critical Function), where the lte.cgi endpoint accepts POST requests with the 'Command=Reboot' parameter without verifying the sender's identity. This CGI script appears to be a management interface that should require authentication but fails to implement any access controls, allowing anyone who can reach the router's web interface to trigger administrative actions.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 8.7 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Lifecycle Timeline

3
CVSS changed
Apr 14, 2026 - 17:07 NVD
7.5 (HIGH) 8.7 (HIGH)
PoC Detected
Mar 16, 2026 - 14:53 vuln.today
Public exploit code
CVE Published
Mar 16, 2026 - 01:28 nvd
HIGH 7.5

DescriptionCVE.org

Telesquare SKT LTE Router SDT-CS3B1 software version 1.2.0 contains an unauthenticated remote reboot vulnerability that allows attackers to trigger device reboot without authentication. Attackers can send POST requests to the lte.cgi endpoint with the Command=Reboot parameter to cause denial of service by forcing the router to restart.

Executive ViewAI

Why It Matters

An unauthenticated remote reboot vulnerability in Telesquare SKT LTE Router SDT-CS3B1 (firmware 1.2.0) allows attackers to remotely disable affected devices without credentials, creating a denial of service risk for any organization relying on these routers for network connectivity. With public exploits available and no vendor patch forthcoming, immediate action is required to identify affected devices and implement protective measures to prevent service disruption.

Business Impact: High
Compensating Controls

Network segmentation: isolate management interfaces behind firewall rules restricting POST access to lte.cgi. WAF/IDS rules: block POST requests containing exploit payloads to vulnerable endpoint. Disable remote management: if not required operationally, disable HTTP/HTTPS management access externally. SNMP/SSH-only management: restrict administrative access to secure protocols only. Monitor: enable device restart logging and configure alerts for unexpected reboot events. Consider replacement: evaluate upgrading to alternative routers with active vendor security support.

Threat Intelligence Overview

EPSS Score
0.2%
Top 60% exploitable
Exploit
POC
Public exploit code exists
Data Quality
5 sources
Confidence: Medium

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 0.2%
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· derived
Out-of-Cycle
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
High

Priority Score

64
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +44
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

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