What is the CVSS score of CVE-2026-0640?

CVE-2026-0640 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: 0.1%.

Is there a public PoC exploit available for CVE-2026-0640?

Yes, a public proof-of-concept exploit is available for CVE-2026-0640. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-0640?

Within 7 days: Identify all affected systems and apply vendor patches promptly. Monitor vendor channels for patch availability.

Ac23 Firmware CVE-2026-0640

HIGH

Buffer Overflow (CWE-119)

2026-01-06 cna@vuldb.com

Buffer Overflow Tenda Ac23 Firmware

7.4

CVSS 4.0 · Vendor: vuldb

View

Attack ChainAIDerived

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

Access

Authenticate to Tenda AC23 web interface
Delivery

Send crafted HTTP POST to /goform/PowerSaveSet
Exploit

Manipulate Time parameter with oversized input
Execution

Trigger buffer overflow in sscanf function
Impact

Execute arbitrary code with router 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Weakness	CWE CWE-119 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, buffer size validation MITRE ATT&CK 2 techniques across 2 tactics: Execution,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 AC23 running firmware 16.03.07.52 with web management interface accessible; attacker requires valid login credentials to access /goform/PowerSaveSet endpoint.
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 vulnerability to 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

Buffer overflow in Tenda AC23 firmware version 16.03.07.52 allows remote attackers with low privileges to achieve complete system compromise through a malformed Time parameter in the /goform/PowerSaveSet function. Public exploit code exists for this vulnerability, creating immediate risk to affected devices. No patch is currently available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 8.8

A weakness has been identified in Tenda AC23 16.03.07.52. This affects the function sscanf of the file /goform/PowerSaveSet. [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 Ac23 Firmware. A weakness has been identified in Tenda AC23 16.03.07.52. This affects the function sscanf of the file /goform/PowerSaveSet. Executing a manipulation of the argument Time can lead to buffer overflow. The attack can be launched 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

Vendor (vuldb) 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 Vendor (vuldb) · only source for this CVE.

CVSS VectorVendor: vuldb

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

CVSS changed

Oct 26, 2026 - 21:23 NVD

8.8 (HIGH) 7.4 (HIGH)

PoC Detected

Jan 15, 2026 - 19:17 vuln.today

Public exploit code

CVE Published

Jan 06, 2026 - 16:15 nvd

HIGH 8.8

DescriptionCVE.org

A weakness has been identified in Tenda AC23 16.03.07.52. This affects the function sscanf of the file /goform/PowerSaveSet. Executing a manipulation of the argument Time can lead to buffer overflow. The attack can be launched remotely. The exploit has been made available to the public and could be used for attacks.

Executive ViewAI

Why It Matters

Organizations using A weakness face significant risk from CVE-2026-0640, a buffer overflow vulnerability rated CVSS 8.8. 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: Severe

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

0.1%

Top 73% 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

Out-of-Cycle

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact

Very High

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.