What is the CVSS score of CVE-2026-2191?

CVE-2026-2191 has a CVSS 3.1 base score of 7.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

Is there a public PoC exploit available for CVE-2026-2191?

Yes, a public proof-of-concept exploit is available for CVE-2026-2191. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-2191?

Within 24 hours: Inventory all Tenda AC9 15.03.06.42_multi devices in your network and isolate or restrict external access to affected units. Within 7 days: Implement network segmentation to limit lateral movement if a device is compromised, and disable the DDoS defense feature if operationally feasible. Within 30 days: Contact Tenda for patch availability and develop a replacement strategy for affected devices, prioritizing units exposed to untrusted networks.

Ac9 Firmware CVE-2026-2191

HIGH

Buffer Overflow (CWE-119)

2026-02-08 cna@vuldb.com

Buffer Overflow Stack Overflow Tenda Ac9 Firmware

7.2

CVSS 3.1 · NVD

View

Attack ChainAIDerived

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

Access

Authenticate as high-privilege admin
Exploit

Send malicious security.ddos.map parameter
Execution

Trigger stack buffer overflow in formGetDdosDefenceList
Impact

Execute arbitrary code

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Weakness	CWE CWE-119 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, buffer size validation MITRE ATT&CK 2 techniques across 2 tactics: Execution,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 AC9 firmware version 15.03.06.42_multi with admin-level authentication required. Attacker must have valid high-privilege credentials to access the vulnerable formGetDdosDefenceList function via the web interface.
Impact	CVSS 7.2 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: High. 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

Stack overflow in Tenda AC9 firmware versions up to 15.03.06.42_multi allows remote attackers with high privileges to achieve complete system compromise through manipulation of the security.ddos.map parameter. Public exploit code exists for this vulnerability, increasing exploitation risk. No patch is currently available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:55 CVSS 7.2

A weakness has been identified in Tenda AC9 15.03.06.42_multi. Affected is the function formGetDdosDefenceList. [CVSS 7.2 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 Ac9 Firmware. A weakness has been identified in Tenda AC9 15.03.06.42_multi. Affected is the function formGetDdosDefenceList. This manipulation of the argument security.ddos.map causes stack-based buffer overflow. The attack may be initiated remotely. The exploit has been made available to the public and could be used for attacks.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.2 HIGH

AV:N/AC:L/PR:H/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

High

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

PoC Detected

Feb 10, 2026 - 15:09 vuln.today

Public exploit code

CVE Published

Feb 08, 2026 - 23:15 nvd

HIGH 7.2

DescriptionCVE.org

A weakness has been identified in Tenda AC9 15.03.06.42_multi. Affected is the function formGetDdosDefenceList. This manipulation of the argument security.ddos.map causes stack-based buffer overflow. The attack may be initiated remotely. The exploit has been made available to the public and could be used for attacks.

Executive ViewAI

Why It Matters

A high-severity vulnerability in Tenda AC9 routers (CVE-2026-2191) allows remote attackers to exploit the DDoS defense function with a CVSS score of 7.2. Organizations using affected Tenda AC9 devices are at risk of unauthorized access and potential network disruption, and this vulnerability is currently publicly exploitable with no patch available from the vendor.

Business Impact: High

Compensating Controls

Disable the formGetDdosDefenceList function if administratively accessible; implement network segmentation to restrict device access to trusted networks only; deploy WAF rules to block suspicious requests targeting the DDoS defense interface; monitor and log all access attempts to affected devices; consider replacing Tenda AC9 units with alternative vendors that provide regular security updates.

Threat Intelligence Overview

EPSS Score

0.1%

Top 72% 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: +36

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.