CVE-2018-8343: Microsoft Windows 7: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified

What, why and how

An elevation of privilege vulnerability exists in the Network Driver Interface Specification (NDIS) when ndis.sys fails to check the length of a buffer prior to copying memory to it, aka "Windows NDIS Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers. This CVE ID is unique from CVE-2018-8342.

What

Why

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

What

Why

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may gain additional privileges.

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: local access → Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') → gain additional privileges
Attack surface: Local
Privileges required: Low: a basic authenticated account is required
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-120 ↗
CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow'). The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Common Vulnerability Scoring System 3.0: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land: The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.

Privilege escalationCWE-120

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2018-19994Official EUVD mapping

0 linked advisory records.

Official EUVD record ↗

CERT-FR · French · CERTFR-2018-AVI-397Multiples vulnérabilités dans Microsoft Windows

crosoft.com/fr-FR/security-guidance Référence CVE CVE-2018-0952 https://www.cve.org/CVERecord?id=CVE-2018-0952 Référence CVE CVE-2018-8200 https://www.cve.org/CVERecord?id=CVE-2018-8200 Référence CVE CVE-2018-8204 https://www.cve.org/CVERecord?id=CVE-2018-8204 Référence CVE CVE-2018-8253 https://www.cve.org/CVERecord?id=CVE-2018-8253 Référence CVE CVE-2018-8339 https://www.cve.org/CVERecord?id=CVE-2018-8339 Référence CVE CVE-2018-8340 https://www.cve.org/CVERecord?id=CVE-2018-8340 Référence CVE CVE-2018-8341 https://www.cve.org/CVERecord?id=CVE-2018-8341 Référence CVE CVE-2018-8342 https://www.cve.org/CVERecord?id=CVE-2018-8342 Référence CVE CVE-2018-8343 https://www.cve.org/CVERecord?id=CVE-2018-8343 Référence CVE CVE-2018-8344 https://www.cve.org/CVERecord?id=CVE-2018-8344 Référence CVE CVE-2018-8345 https://www.cve.org/CVERecord?id=CVE-2018-8345 Référence CVE CVE-2018-8346 https://www.cve.org/CVERecord?id=CVE-2018-8346 Référence CVE CVE-2018-8347 https://www.cve.org/CVERecord?id=CVE-2018-8347 Référence CVE CVE-2018-8348 https://www.cve.org/CVERecord?id=CVE-2018-8348 Référence CVE CVE-2018-8349 https://www.cve.org/CVERecord?id=CVE-2018-8349 Référence CVE CVE-2018-8350 https://www.cve.org/CVERecord?id=CVE-2018-8350 Référence CVE CVE-2018-8394 https://www.cve.org/CVERecord?id=CVE-2018-8394 Ré

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2018-008727Microsoft Windows 7 および Windows Server 2008 R2 の Network Driver Interface Specification における権限を昇格される脆弱性

Microsoft Windows 7 および Windows Server 2008 R2 の Network Driver Interface Specification (NDIS) には、ndis.sys がバッファにメモリをコピーする前にバッファ長の検証に失敗した場合、権限を昇格される脆弱性が存在します。ベンダは、本脆弱性を「Windows NDIS の特権の昇格の脆弱性」として公開しています。本脆弱性は、CVE-2018-8343 とは異なる脆弱性です。

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2018-007870複数の Microsoft Windows 製品の Network Driver Interface Specification (NDIS) における権限を昇格される脆弱性

複数の Microsoft Windows 製品の Network Driver Interface Specification (NDIS) には、ndis.sys がバッファー長の検証に失敗した場合、権限を昇格される脆弱性が存在します。ベンダは、本脆弱性を「Windows NDIS の特権の昇格の脆弱性」として公開しています。本脆弱性は、CVE-2018-8342 とは異なる脆弱性です。

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-4898MS 8월 보안 위협에 따른 정기 보안 업데이트 권고

- 권한상승 취약점(CVE-2018-0952,CVE-2018-8253,CVE-2018-8339,CVE-2018-8343,CVE-2018-8347,CVE-2018-8357,CVE-2018-8399,CVE-2018-8400,CVE-2018-8401,CVE-2018-8404,CVE-2018-8405,CVE-2018-8406)

Official advisory ↗

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Fix not verified
Affected: Windows 7: 32-bit Systems Service Pack 1, x64-based Systems Service Pack 1
Windows Server 2012 R2: (Server Core installation)
Windows RT 8.1: Windows RT 8.1
Windows Server 2012: (Server Core installation)
Windows 8.1: 32-bit systems, x64-based systems
Windows Server 2016: (Server Core installation)
Windows Server 2008 R2: Itanium-Based Systems Service Pack 1, x64-based Systems Service Pack 1, x64-based Systems Service Pack 1 (Server Core installation)
Windows 10: 32-bit Systems, Version 1607 for 32-bit Systems, Version 1607 for x64-based Systems, Version 1703 for 32-bit Systems, Version 1703 for x64-based Systems, Version 1709 for 32-bit Systems, Version 1709 for x64-based Systems, Version 1803 for 32-bit Systems, Version 1803 for x64-based Systems, x64-based Systems
Windows 10 Servers: version 1709 (Server Core Installation), version 1803 (Server Core Installation)
Fixed: No fixed version is explicitly recorded in the structured CVE data.
Action: No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround: No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.

Evidence and provenance

Published 15 Aug 2018 · Last source change 5 Aug 2024, 06:54 UTC · CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVE recordCVE.org · 5.1

CVSS sourceNIST NVD

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-09-01

European sourceENISA EUVD · EUVD-2018-19994

Product sourceCNA

Remediation sourceCVE/CNA references

CWE sourceNIST NVD

NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

1 Sep 2026, 02:42 UTC
ENISA EUVD mappingEUVD-2018-19994 was added to the official ENISA EUVD mapping for this CVE.
Before
not recorded
After
{"euvdId":"EUVD-2018-19994"}
ENISA EUVD ↗
5 Aug 2024, 06:54 UTC
Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: portal.msrc.microsoft.com/CVE-2018-8343.
Before
no authoritative guidance recorded
After
vendor advisory: portal.msrc.microsoft.com/CVE-2018-8343
portal.msrc.microsoft.com ↗
5 Aug 2024, 06:54 UTC
SeveritySeverity changed from Unknown to High.
Before
Unknown
After
High
NIST NVD ↗
5 Aug 2024, 06:54 UTC
CVSS scoreCVSS score changed from not recorded to 7.8 (CVSS 3.0 · NIST NVD · CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
Before
not recorded
After
7.8 (CVSS 3.0 · NIST NVD · CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
NIST NVD ↗
5 Aug 2024, 06:54 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2018-08-15CVE published

ENISA EUVD · EUVD-2018-19994↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

Microsoft Windows 7: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Published severity in operational context

Evidence used

Compensating controls

Verification

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

ENISA European Vulnerability Database

EUVD-2018-19994

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication