What is the CVSS score of CVE-2026-2877?

CVE-2026-2877 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%.

How to fix or mitigate CVE-2026-2877?

Within 24 hours: Inventory all Tenda A18 devices running firmware 15.13.07.13 and isolate affected units from production networks if possible. Within 7 days: Implement network segmentation to restrict administrative access to these devices and enable WAF rules blocking malformed requests to /goform/WifiExtraSet endpoint. Within 30 days: Contact Tenda for firmware availability; if no patch emerges, evaluate replacement with patched router models and decommission vulnerable units from security-critical network segments.

A18 Firmware CVE-2026-2877

HIGH

Buffer Overflow (CWE-119)

2026-02-21 cna@vuldb.com

Buffer Overflow Stack Overflow Tenda A18 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 A18 web interface
Delivery

Send crafted POST request to /goform/WifiExtraSet
Exploit

Inject oversized wpapsk_crypto5g parameter
Execution

Overflow stack buffer in strcpy function
Impact

Execute arbitrary code as httpd service

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Weakness	CWE CWE-119 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, buffer size validation MITRE ATT&CK 2 techniques across 2 tactics: Execution,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 A18 firmware 15.13.07.13 with Httpd service enabled. Attacker requires valid authentication credentials to access /goform/WifiExtraSet endpoint. Default-deployed Tenda A18 routers with unchanged login credentials are vulnerable.
Impact	CVSS 8.8 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: Low. User interaction: None. Exploitable via remote/network.
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-based buffer overflow in Tenda A18 firmware versions up to 15.13.07.13 allows remote attackers with low privileges to achieve code execution through the wpapsk_crypto5g parameter in the /goform/WifiExtraSet endpoint. Public exploit code exists for this vulnerability, and no patch is currently available. The high CVSS score (8.8) reflects the combination of remote exploitability and complete system compromise potential.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 22:04 CVSS 8.8

A vulnerability has been found in Tenda A18 15.13.07.13. This affects the function strcpy of the file /goform/WifiExtraSet of the component Httpd Service. [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 A18 Firmware. A vulnerability has been found in Tenda A18 15.13.07.13. This affects the function strcpy of the file /goform/WifiExtraSet of the component Httpd Service. The manipulation of the argument wpapsk_crypto5g leads to stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may 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

DescriptionCVE.org

A vulnerability has been found in Tenda A18 15.13.07.13. This affects the function strcpy of the file /goform/WifiExtraSet of the component Httpd Service. The manipulation of the argument wpapsk_crypto5g leads to stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used.

Executive ViewAI

Why It Matters

A critical buffer overflow vulnerability affects Tenda A18 wireless router models running firmware 15.13.07.13, allowing unauthenticated remote attackers to execute arbitrary code and potentially compromise network infrastructure. Organizations using this equipment face immediate risk of unauthorized access to their network perimeter and sensitive data.

Business Impact: High

Compensating Controls

Implement network access controls to restrict management traffic to Tenda A18 devices; deploy Web Application Firewall rules to block HTTP requests containing strcpy overflow payloads targeting /goform/WifiExtraSet; isolate affected routers on a segregated management VLAN; disable WifiExtraSet functionality if firmware allows; monitor for suspicious HTTP activity on port 80/443 targeting these endpoints; consider temporary replacement with alternative router hardware until patch availability is confirmed.

Threat Intelligence Overview

EPSS Score

0.1%

Top 78% exploitable

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 No

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

None

System Exposure· derived

Open

Automatable· derived

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +44

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.

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.