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W20e Firmware CVE-2026-24108

CRITICAL
Classic Buffer Overflow (CWE-120)
2026-03-02 cve@mitre.org
9.8
CVSS 3.1 · NVD
View

Attack ChainAIDerived

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

  1. Access
    Send crafted HTTP request with oversized nptr parameter
  2. Delivery
    Parameter passed to getMibPrefix function
  3. Exploit
    sprintf concatenates without bounds checking
  4. Execution
    Buffer overflow overwrites memory
  5. Impact
    Execute arbitrary code with device privileges

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Buffer copy size validation
MITRE ATT&CK

1 technique 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

Tenda W20E running firmware V4.0br_V15.11.0.6 with default configuration exposing the vulnerable getMibPrefix function endpoint to unauthenticated network access. No authentication or special network setup required.

Impact

CVSS 9.8 with PoC.

Exploit ScenarioDerived

Buffer overflow via crafted HTTP request.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Tenda W20E has a buffer overflow — second of eight critical vulnerabilities in this router firmware.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 21:55 CVSS 9.8

Second Tenda W20E buffer overflow.

RemediationAI

Update firmware.

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

CWE-120 in Tenda W20E.

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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

Lifecycle Timeline

2
PoC Detected
Mar 03, 2026 - 15:54 vuln.today
Public exploit code
CVE Published
Mar 02, 2026 - 15:16 nvd
CRITICAL 9.8

DescriptionCVE.org

An issue was discovered in Tenda W20E V4.0br_V15.11.0.6. Attackers may exploit the vulnerability by controlling the value of nptr. When this value is passed into the getMibPrefix function and concatenated using sprintf without proper size validation, it could lead to a buffer overflow vulnerability.

Executive ViewAI

Why It Matters

A critical vulnerability (CVE-2026-24108) affecting Tenda W20E routers allows remote attackers to gain unauthorized control with a CVSS score of 9.8. Organizations using this device model are at immediate risk of network compromise, data exfiltration, and potential lateral movement into corporate infrastructure, particularly if these devices serve as network entry points or manage critical connectivity.

Business Impact: Severe
Compensating Controls

Implement network segmentation isolating Tenda W20E devices from critical systems; disable remote administration and UPnP features; deploy WAF/IPS rules to detect exploitation attempts targeting the nptr parameter; restrict management access to whitelisted IP addresses only; increase logging and monitoring for these devices; consider temporary shutdown of non-essential W20E units until patching is available.

Threat Intelligence Overview

EPSS Score
0.1%
Top 84% exploitable
Exploit
POC
Public exploit code exists
Data Quality
4 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 CRITICAL
CISA KEV No
Public POC Yes
EPSS 0.1%
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
Out-of-Cycle
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Very High

Priority Score

69
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +49
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Affected Products (CPE)CVE.org

cpe:2.3:o:tenda:w20e_firmware:15.11.0.6:*:*:*:*:*:*:*

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