What is the CVSS score of CVE-2023-40166?

CVE-2023-40166 has a CVSS 3.1 base score of 5.5 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.5%.

Is there a public PoC exploit available for CVE-2023-40166?

Yes, a public proof-of-concept exploit is available for CVE-2023-40166. Prioritise patching immediately. EPSS: 0.5%.

Notepad CVE-2023-40166

MEDIUM

Classic Buffer Overflow (CWE-120)

2023-08-25 security-advisories@github.com

Buffer Overflow Notepad Notepad Plus Plus

5.5

CVSS 3.1 · NVD

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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 score of 5.5 (MEDIUM). Attack characteristics: local attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	A local attacker with access to the system could overflow a buffer to corrupt adjacent memory. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

No patch listed yet 0.5% exploitation probability (EPSS)

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AnalysisAI

Notepad++ is a free and open-source source code editor. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, 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. Always validate buffer sizes before copy operations. Use bounded functions (strncpy, snprintf). Enable compiler protections.

Affects your stack

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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 Copy without Size Check (CWE-120), which allows attackers to overflow a buffer to corrupt adjacent memory. Notepad++ is a free and open-source source code editor. Versions 8.5.6 and prior are vulnerable to heap buffer read overflow in FileManager::detectLanguageFromTextBegining . The exploitability of this issue is not clear. Potentially, it may be used to leak internal memory allocation information. As of time of publication, no known patches are available in existing versions of Notepad++. Affected products include: Notepad-Plus-Plus Notepad\+\+.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.5 MEDIUM

AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

DescriptionNVD

Notepad++ is a free and open-source source code editor. Versions 8.5.6 and prior are vulnerable to heap buffer read overflow in FileManager::detectLanguageFromTextBegining . The exploitability of this issue is not clear. Potentially, it may be used to leak internal memory allocation information. As of time of publication, no known patches are available in existing versions of Notepad++.

Threat Intelligence Overview

EPSS Score

0.5%

Top 62% exploitable

Exploit

POC

Public exploit code exists

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

GitHub

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 MEDIUM

CISA KEV No

Public POC Yes

EPSS 0.5%

Patch available No

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

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

Small

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +28

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.