What is the CVSS score of EUVD-2025-209313?

EUVD-2025-209313 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

How to fix or mitigate EUVD-2025-209313?

Within 24 hours: Identify all Tenda AC6 routers in your environment and their current firmware versions via network inventory scan. Within 7 days: Check Tenda security advisories for firmware updates; if available, test and deploy to non-production devices first. Within 30 days: Complete production deployment of patched firmware to all affected Tenda AC6 units, prioritizing business-critical network segments. If firmware updates are unavailable from Tenda, implement network-level access controls to restrict HTTP access to router management interfaces from untrusted networks.

N A EUVD-2025-209313

| CVE-2025-52221 CRITICAL

Classic Buffer Overflow (CWE-120)

2026-04-08 mitre

Buffer Overflow Tenda N A

9.8

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-120 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. Sign in to read
Impact	CVSS 7.5 reflects high availability impact via unauthenticated network exploitation of Tenda AC6 firmware. Low EPSS (0.02%) indicates low observed exploitation activity. Risk remains elevated due to trivial attack complexity and direct accessibility to IoT devices, though mitigation likelihood depends on device exposure and patch availability from vendor.
Exploit ScenarioDerived	Attacker sends crafted HTTP request to formSetCfm function with oversized funcname, funcpara1, or funcpara2 parameters. Overflow overwrites memory, causing denial of service. Publicly available exploit code exists in GitHub repositories referenced; no authentication required.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Apr 08, 2026

Buffer overflow in Tenda AC6 router firmware version 15.03.05.16_multi enables unauthenticated remote denial-of-service attacks via crafted HTTP requests to formSetCfm function. Attackers can trigger service disruption by sending malicious funcname, funcpara1, or funcpara2 parameters without authentication. The network-accessible attack vector with low complexity makes this exploitable from the internet. No public exploit identified at time of analysis. Low observed exploitation activity (EPSS 0.02%).

RemediationAI

No vendor-released patch identified at time of analysis. Tenda has not published security advisory or firmware update addressing CVE-2025-52221 for AC6 15.03.05.16_multi. Users should monitor Tenda official support portal for firmware releases. Immediate mitigations: disable remote administration interface, restrict web management access to trusted internal IP ranges via firewall rules, place device behind network segmentation boundaries. Consider hardware replacement if vendor discontinues AC6 support. Technical analysis available at https://github.com/faqiadegege/IoTVuln/blob/main/tendaAc6_formSetCfm_funcname_overflow/detail.md and NVD advisory https://nvd.nist.gov/vuln/detail/CVE-2025-52221 for monitoring patch availability.

Affected VersionsENISA

n/a n/a

Affects your stack

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Technical ContextAI · show details

CWE-120 buffer overflow in formSetCfm function results from inadequate input validation on three HTTP parameters. Network-reachable web interface accepts oversized parameter strings, causing stack or heap corruption that terminates service availability. CVSS vector PR:N confirms unauthenticated attack surface directly exposed to WAN/LAN requests.

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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

Severity Changed

Apr 13, 2026 - 11:37 NVD

HIGH CRITICAL

CVSS changed

Apr 13, 2026 - 11:37 NVD

7.5 (HIGH) 9.8 (CRITICAL)

CVE Published

Apr 08, 2026 - 00:00 nvd

HIGH 7.5

DescriptionNVD

Tenda AC6 15.03.05.16_multi is vulnerable to Buffer Overflow in the formSetCfm function via the funcname, funcpara1, and funcpara2 parameters.

Executive ViewAI

Why It Matters

Tenda AC6 routers running firmware 15.03.05.16_multi are vulnerable to unauthenticated remote denial-of-service attacks that can disable network connectivity for all users behind the affected device. Any internet-connected attacker can trigger a service outage by sending specially crafted HTTP requests without credentials, creating business continuity risk for organizations relying on these devices for network access.

Business Impact: High

Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: (1) Restrict HTTP access to router management interfaces via firewall rules-only allow administrative access from trusted IP ranges; (2) Deploy network segmentation to limit impact radius of router compromise; (3) Monitor router CPU and service availability for anomalous behavior; (4) Enable router-level logging if available and review for suspicious HTTP requests; (5) Maintain current configuration backups to enable rapid restoration if denial-of-service occurs.

Threat Intelligence Overview

EPSS Score

0.0%

Top 95% exploitable

Data Quality

6 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS

Vulnrichment

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 CRITICAL

CISA KEV No

Public POC No

EPSS 0.0%

Patch available No

Active threat No

Deciding rule

CRITICAL severity

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

Scheduled

Exploitation

None

System Exposure· derived

Open

Automatable

Yes

Human Impact

High

Technical Impact

Partial

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +49

PoC: 0

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.