What is the CVSS score of CVE-2025-8940?

CVE-2025-8940 has a CVSS 4.0 base score of 7.4 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P. EPSS exploitation probability: 0.5%.

Is there a public PoC exploit available for CVE-2025-8940?

Yes, a public proof-of-concept exploit is available for CVE-2025-8940. Prioritise patching immediately. EPSS: 0.5%.

How to fix or mitigate CVE-2025-8940?

Within 30 days: Identify all affected systems running Tenda AC20 and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

Ac20 Firmware CVE-2025-8940

HIGH

Buffer Overflow (CWE-119)

2025-08-14 cna@vuldb.com

Buffer Overflow Tenda Ac20 Firmware

7.4

CVSS 4.0 · NVD

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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Weakness	CWE CWE-119 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, buffer size validation MITRE ATT&CK 2 techniques across 2 tactics: Execution,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
Impact	CVSS score of 7.4 (HIGH). Attack characteristics: network attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.47%.
Exploit ScenarioDerived	A remote attacker could corrupt memory to execute arbitrary code or crash the application by sending crafted requests to the affected application.

This Month Plan within 30 days. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.5% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

A vulnerability was identified in Tenda AC20 up to 16.03.08.12. Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use memory-safe languages or bounds-checking. Enable ASLR, DEP/NX, stack canaries. Use safe string functions.

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

This vulnerability is classified as Buffer Overflow (CWE-119), which allows attackers to corrupt memory to execute arbitrary code or crash the application. A vulnerability was identified in Tenda AC20 up to 16.03.08.12. Affected by this vulnerability is the function strcpy of the file /goform/saveParentControlInfo. The manipulation of the argument Time leads to buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. Affected products include: Tenda Ac20 Firmware. Version information: up to 16.03.08.12..

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.4 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

None

Privileges Required

Low

User Interaction

None

Vulnerable system: Confidentiality

High

Vulnerable system: Integrity

High

Vulnerable system: Availability

High

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

Lifecycle Timeline

PoC Detected

Aug 19, 2025 - 18:42 vuln.today

Public exploit code

CVE Published

Aug 14, 2025 - 06:15 nvd

HIGH 7.4

DescriptionCVE.org

A vulnerability was identified in Tenda AC20 up to 16.03.08.12. Affected by this vulnerability is the function strcpy of the file /goform/saveParentControlInfo. The manipulation of the argument Time leads to buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used.

Executive ViewAI

Why It Matters

Organizations using Tenda AC20 face moderate risk from CVE-2025-8940, a buffer overflow vulnerability rated CVSS 7.4. Exploitation could allow attackers to corrupt memory, crash the application, or potentially execute arbitrary code. Proof-of-concept code is publicly available, increasing the risk of exploitation. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: Moderate

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score

0.5%

Top 35% exploitable

Exploit

POC

Public exploit code exists

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 0.5%

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

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +37

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.