What is the CVSS score of CVE-2026-3678?

CVE-2026-3678 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

Is there a public PoC exploit available for CVE-2026-3678?

Yes, a public proof-of-concept exploit is available for CVE-2026-3678. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-3678?

Within 24 hours: Inventory all Tenda FH451 1.0.0.9 devices in your environment and isolate affected units from production networks if possible. Within 7 days: Implement network segmentation to restrict administrative access to these devices and enable enhanced logging on network perimeter devices. Within 30 days: Develop a replacement strategy with vendors and plan device migration to alternative manufacturers with active security support.

Fh451 Firmware CVE-2026-3678

HIGH

Buffer Overflow (CWE-119)

2026-03-07 cna@vuldb.com

Buffer Overflow Stack Overflow Tenda Fh451 Firmware

8.8

CVSS 3.1 · NVD

View

Attack ChainAIDerived

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

Access

Authenticate to Tenda FH451 web interface
Delivery

Send POST request to /goform/AdvSetWan
Exploit

Inject oversized payload in wanmode/PPPOEPassword parameter
Execution

Overflow stack buffer in sub_3C434
Impact

Execute arbitrary code with device privileges

Vulnerability Assessment

Weakness	CWE CWE-119 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, buffer size validation MITRE ATT&CK 2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	Tenda FH451 firmware version 1.0.0.9 with web management interface enabled; valid user credentials required for authentication to /goform/AdvSetWan endpoint; stack-based buffer overflow triggered via wanmode or PPPOEPassword parameters in HTTP POST request.
Impact	CVSS 8.8 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: Low. User interaction: None. Exploitable via remote/network. Public exploit/POC available.
Exploit ScenarioDerived	A remote attacker could exploit this vulnerability to compromise the affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Remote code execution in Tenda FH451 firmware via stack-based buffer overflow in the WAN configuration endpoint allows unauthenticated attackers to achieve full system compromise through malicious wanmode or PPPOEPassword parameters. Public exploit code exists for this vulnerability, and no patch is currently available. Stack Overflow products are also reported as affected.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:55 CVSS 8.8

A vulnerability was determined in Tenda FH451 1.0.0.9. Affected is the function sub_3C434 of the file /goform/AdvSetWan. [CVSS 8.8 HIGH]

RemediationAI

Monitor vendor advisories for a patch. Enable ASLR, DEP/NX, and stack canaries where possible. Restrict network access to the affected service where possible.

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

Classified as CWE-119 (Buffer Overflow). Affects Fh451 Firmware. A vulnerability was determined in Tenda FH451 1.0.0.9. Affected is the function sub_3C434 of the file /goform/AdvSetWan. This manipulation of the argument wanmode/PPPOEPassword causes stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been publicly disclosed and may be utilized.

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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

PoC Detected

Mar 09, 2026 - 16:16 vuln.today

Public exploit code

CVE Published

Mar 07, 2026 - 23:15 nvd

HIGH 8.8

DescriptionCVE.org

A vulnerability was determined in Tenda FH451 1.0.0.9. Affected is the function sub_3C434 of the file /goform/AdvSetWan. This manipulation of the argument wanmode/PPPOEPassword causes stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been publicly disclosed and may be utilized.

Executive ViewAI

Why It Matters

A high-severity vulnerability (CVSS 8.8) affects Tenda FH451 routers with no patch currently available, creating immediate risk for organizations relying on these devices for network connectivity. Public exploit code exists, increasing the likelihood of active exploitation and potential unauthorized access to network infrastructure.

Business Impact: High

Compensating Controls

Restrict network access to /goform/AdvSetWan endpoint via firewall rules; segment affected routers to isolated network VLANs; disable WAN configuration features if not operationally critical; implement continuous monitoring and IDS/IPS signatures for exploitation attempts; consider deploying a reverse proxy with WAF rules to inspect and block malicious requests to vulnerable endpoints; monitor for firmware updates from Tenda and plan immediate deployment when available.

Threat Intelligence Overview

EPSS Score

0.1%

Top 78% exploitable

Exploit

POC

Public exploit code exists

Data Quality

5 sources

Confidence: Medium

NVD

CVE.org

EPSS

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 0.1%

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

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +44

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

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.

Stack-based Buffer Overflow HIGH

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.