What is the CVSS score of CVE-2026-3677?

CVE-2026-3677 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-2026-3677?

Yes, a public proof-of-concept exploit is available for CVE-2026-3677. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-3677?

Within 24 hours: Inventory all Tenda FH451 1.0.0.9 devices across your organization and isolate affected units from production networks if operationally feasible. Within 7 days: Implement network segmentation to restrict access to the vulnerable devices, disable the /goform/setcfm endpoint via WAF or firewall rules if possible, and deploy enhanced monitoring for suspicious activities targeting these devices. Within 30 days: Develop a device replacement plan, evaluate alternative router vendors, and conduct a security assessment of any systems that may have been compromised through these devices.

Fh451 Firmware CVE-2026-3677

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
Exploit

Send crafted POST request to /goform/setcfm
Execution

Overflow stack buffer via funcname/funcpara1 parameters
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Weakness	CWE CWE-119 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, buffer size validation MITRE ATT&CK 2 techniques across 2 tactics: Execution,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 accessible. Requires valid login credentials to access /goform/setcfm endpoint. The setcfm function must be enabled in device configuration.
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 flaw, stack-based buffer overflow.

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

Stack overflow in Tenda FH451 firmware's setcfm function allows authenticated remote attackers to achieve complete system compromise through malicious funcname or funcpara1 parameters. Public exploit code exists for this vulnerability, and no patch is currently available. The flaw affects firmware version 1.0.0.9 and enables remote code execution with high impact to confidentiality, integrity, and availability.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:55 CVSS 8.8

A vulnerability was found in Tenda FH451 1.0.0.9. This impacts the function fromSetCfm of the file /goform/setcfm. [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 found in Tenda FH451 1.0.0.9. This impacts the function fromSetCfm of the file /goform/setcfm. The manipulation of the argument funcname/funcpara1 results in stack-based buffer overflow. The attack may be performed from remote. The exploit has been made public and could be used.

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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 - 22:15 nvd

HIGH 8.8

DescriptionCVE.org

A vulnerability was found in Tenda FH451 1.0.0.9. This impacts the function fromSetCfm of the file /goform/setcfm. The manipulation of the argument funcname/funcpara1 results in stack-based buffer overflow. The attack may be performed from remote. The exploit has been made public and could be used.

Executive ViewAI

Why It Matters

A high-severity vulnerability (CVE-2026-3677) affecting Tenda FH451 routers has been publicly disclosed with working exploits available, but no patch has been released by the vendor. Organizations using this router model face immediate risk of unauthorized access and system compromise. This requires urgent action to protect network integrity and prevent potential data breaches.

Business Impact: High

Compensating Controls

Implement Web Application Firewall (WAF) rules to block access to /goform/setcfm endpoint; restrict administrative access to affected routers through network segmentation and firewall ACLs; disable remote management functionality if not critical; increase logging and monitoring for exploitation attempts; consider replacing affected devices with patched alternatives from the vendor or competing manufacturers; apply vendor firmware updates immediately if any become available.

Threat Intelligence Overview

EPSS Score

0.1%

Top 77% 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.