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Bl Wr9000 EUVDEUVD-2026-12367

| CVE-2026-4226 HIGH
Stack-based Buffer Overflow (CWE-121)
2026-03-16 VulDB
8.8
CVSS 3.1 · NVD
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Attack ChainAIDerived

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

  1. Access
    Authenticate to LB-LINK BL-WR9000
  2. Exploit
    Send crafted request to /goform/get_virtual_cfg
  3. Execution
    Trigger stack buffer overflow in sub_44E8D0
  4. 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A06:2021 - Vulnerable and Outdated Components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 Stack buffer bounds checking
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

LB-LINK BL-WR9000 firmware version 2.4.9 with /goform/get_virtual_cfg endpoint accessible. Valid authentication credentials required. Attacker must have network access to device's web interface on default ports.

Impact

The CVSS 3.1 score of 8.8 (High) reflects significant risk with network-based attack vector (AV:N), low complexity (AC:L), and low privileges required (PR:L), enabling full compromise of confidentiality, integrity, and availability. The presence of a public proof-of-concept exploit (E:P) dramatically increases real-world risk. While not currently listed in CISA's KEV catalog, the combination of a publicly available exploit, ease of exploitation (low complexity), and the fact that only low privileges are required makes this a high-priority vulnerability for organizations using affected devices. The vendor's lack of response to disclosure attempts further elevates risk as no patch appears forthcoming.

Exploit ScenarioDerived

An attacker with low-privileged credentials to the router's web interface sends a specially crafted request to the /goform/get_virtual_cfg endpoint containing an oversized payload that overflows the stack buffer in function sub_44E8D0. This allows the attacker to overwrite the return address and execute arbitrary code with the privileges of the web server process, potentially gaining full control of the router. A detailed proof-of-concept demonstrating this attack is publicly available at https://github.com/glkfc/IoT-Vulnerability/blob/main/LB-LINK/LB-LINK_VirtualRules%20stack%20overflow_EN.md.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 16, 2026

Stack Overflow's infrastructure contains a stack-based buffer overflow in a virtual configuration function that can be exploited remotely by authenticated attackers to achieve complete system compromise. Public exploit code is available for this vulnerability, and no patch has been released despite vendor notification. An attacker with valid credentials can manipulate input to the vulnerable endpoint and execute arbitrary code with full system privileges.

Earlier versions of this analysis (1)
v1 Mar 16, 2026 - 09:00 CVSS 8.8

A stack-based buffer overflow vulnerability exists in the LB-LINK BL-WR9000 router firmware version 2.4.9, specifically in the function sub_44E8D0 within the /goform/get_virtual_cfg endpoint. This vulnerability allows authenticated remote attackers to potentially execute arbitrary code, leading to complete compromise of the device. A public proof-of-concept exploit is available on GitHub, significantly increasing the risk of active exploitation in the wild.

RemediationAI

No patch is currently available as the vendor has not responded to disclosure attempts. Organizations should immediately implement compensating controls including restricting network access to the router's management interface to trusted IP addresses only, disabling the vulnerable /goform/get_virtual_cfg endpoint if possible, and considering replacement with alternative router models from responsive vendors. Monitor the VulDB advisory at https://vuldb.com/?id.351149 for any future updates. Given the lack of vendor support, replacing affected devices should be strongly considered as a long-term solution.

Affected VersionsENISA

BL-WR9000 2.4.9

Affected Packages

euvd bl_wr9000 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 LB-LINK BL-WR9000 router (CPE: cpe:2.3:a:lb-link:bl-wr9000:*:*:*:*:*:*:*:*), specifically version 2.4.9 as confirmed by EUVD-2026-12367. The root cause is a classic stack-based buffer overflow (CWE-121) where the application fails to properly validate input size before copying data to a fixed-size buffer on the stack. This occurs in the sub_44E8D0 function when processing requests to the /goform/get_virtual_cfg endpoint, likely related to virtual configuration management functionality in the router's web interface.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 8.8 HIGH
AV:N/AC:L/PR:L/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
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
PoC Detected
Mar 20, 2026 - 18:21 vuln.today
Public exploit code
CVE Published
Mar 16, 2026 - 07:32 nvd
HIGH 8.8

DescriptionCVE.org

A weakness has been identified in LB-LINK BL-WR9000 2.4.9. The affected element is the function sub_44E8D0 of the file /goform/get_virtual_cfg. Executing a manipulation can lead to stack-based buffer overflow. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Executive ViewAI

Why It Matters

A critical remote code execution vulnerability affecting LB-LINK BL-WR9000 routers (firmware 2.4.9) poses an immediate threat to organizations deploying these devices. With a public exploit available and no vendor patch released, any organization using this router model faces significant risk of network compromise and unauthorized access to internal systems.

Business Impact: Severe
Compensating Controls

Implement Web Application Firewall (WAF) rules to block requests to /goform/get_virtual_cfg endpoint; disable authenticated remote access to the vulnerable endpoint via access control lists; restrict administrative access to router management interfaces to whitelisted IP addresses only; segment router networks to limit lateral movement if compromise occurs; increase monitoring and alerting for suspicious authentication attempts and code execution patterns; consider implementing network-level controls to prevent communication from router to internal systems; evaluate router replacement with alternative vendors as primary mitigation.

Threat Intelligence Overview

EPSS Score
0.0%
Top 88% exploitable
Exploit
POC
Public exploit code exists
Data Quality
6 sources
Confidence: High

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 0.0%
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
No
Human Impact
Very 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

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.

A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.

Related Vulnerabilities in LB-LINK BL-WR9000 Buffer Overflow and Injection

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