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Full vulnerability report · 2020
CVE-2020-0661High confidence

Microsoft Windows — Improper Input Validation

Microsoft · Windows

6.8MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 1.63% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Microsoft Windows and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

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

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2020-2154

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate input from a privileged user on a guest operating system, aka 'Windows Hyper-V Denial of Service Vulnerability'. This CVE ID is unique from CVE-2020-0751.

What

A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate input from a privileged user on a guest operating system, aka 'Windows Hyper-V Denial of Service Vulnerability'. This CVE ID is unique from CVE-2020-0751.

Why

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How

An attacker operating through the affected interface may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.

What

A denial of service vulnerability exists when Microsoft Hyper-V on a host server fails to properly validate input from a privileged user on a guest operating system, aka 'Windows Hyper-V Denial of Service Vulnerability'. This CVE ID is unique from CVE-2020-0751.

Why

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How

An attacker operating through the affected interface may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.

02

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
the affected interface → Improper Input Validation → disrupt the affected service
Attack surface
Unspecified
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-20 ↗

CWE-20: Improper Input Validation. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close network.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.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
Denial of serviceCWE-20
A

Official authority intelligence

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

CERT-FR · French · CERTFR-2020-AVI-081Multiples vulnérabilités dans Microsoft Windows

un déni de service. Solution Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation). Documentation Bulletin de sécurité Microsoft du 10 février 2020 https://portal.msrc.microsoft.com/fr-FR/security-guidance Référence CVE CVE-2020-0655 https://www.cve.org/CVERecord?id=CVE-2020-0655 Référence CVE CVE-2020-0657 https://www.cve.org/CVERecord?id=CVE-2020-0657 Référence CVE CVE-2020-0658 https://www.cve.org/CVERecord?id=CVE-2020-0658 Référence CVE CVE-2020-0659 https://www.cve.org/CVERecord?id=CVE-2020-0659 Référence CVE CVE-2020-0660 https://www.cve.org/CVERecord?id=CVE-2020-0660 Référence CVE CVE-2020-0661 https://www.cve.org/CVERecord?id=CVE-2020-0661 Référence CVE CVE-2020-0662 https://www.cve.org/CVERecord?id=CVE-2020-0662 Référence CVE CVE-2020-0665 https://www.cve.org/CVERecord?id=CVE-2020-0665 Référence CVE CVE-2020-0666 https://www.cve.org/CVERecord?id=CVE-2020-0666 Référence CVE CVE-2020-0667 https://www.cve.org/CVERecord?id=CVE-2020-0667 Référence CVE CVE-2020-0668 https://www.cve.org/CVERecord?id=CVE-2020-0668 Référence CVE CVE-2020-0669 https://www.cve.org/CVERecord?id=CVE-2020-0669 Référence CVE CVE-2020-0670 https://www.cve.org/CVERecord?id=CVE-2020-0670 Référence CVE CVE-2020-0671 https://www.cve.org/CVERecord?id=CVE-2020-0671 Ré

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-001822複数の Microsoft Windows 製品におけるサービス運用妨害 (DoS) の脆弱性

複数の Microsoft Windows 製品には、ホストサーバ上の Microsoft Hyper-V がゲストオペレーティングシステム上の特権ユーザからの入力の適切な検証に失敗した場合、サービス運用妨害 (DoS) の脆弱性が存在します。 ベンダは、本脆弱性を「Windows Hyper-V のサービス拒否の脆弱性」として公開しています。 本脆弱性は、CVE-2020-0751 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-001770Microsoft Windows 10 および Microsoft Windows Server におけるサービス運用妨害 (DoS) の脆弱性

Microsoft Windows 10 および Microsoft Windows Server には、ホストサーバ上の Microsoft Hyper-V がゲストオペレーティングシステム上のユーザからの特定の悪意のあるデータの適切な検証に失敗した場合、サービス運用妨害 (DoS) の脆弱性が存在します。 ベンダは、本脆弱性を「Windows Hyper-V のサービス拒否の脆弱性」として公開しています。 本脆弱性は、CVE-2020-0661 とは異なる脆弱性です。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5096MS 2월 보안 위협에 따른 정기 보안 업데이트 권고

- 서비스거부 취약점(CVE-2020-0660, CVE-2020-0661, CVE-2020-0751)

Official advisory ↗
03

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.
Patch available
Affected
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 11 Feb 2020 · Last source change 4 Aug 2024, 06:11 UTC · CWE-20 · Improper Input Validation

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 2026-08-14
European sourceENISA EUVD · EUVD-2020-2154
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 ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2020-2154↗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.
Free version - for non-commercial use only.CVE-2020-0661 · cve.blacktree.nl