BlackTreeCVE Intelligence
← Back to the CVE catalogue
Full vulnerability report · 2026
CVE-2026-78523High confidence

Windows DNS Server Denial of Service Vulnerability

Microsoft · Windows 10 Version 1607

5.9MediumCVSS 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.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.98% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Microsoft Windows 10 Version 1607 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-2026-73321

No EUVD known-exploited evidence

Use after free in Windows DNS allows an unauthorized attacker to deny service over a network.

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
5.9 · CVSS 3.1
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

Use after free in Windows DNS allows an unauthorized attacker to deny service over a network.

What

Use after free in Windows DNS allows an unauthorized attacker to deny service over a network.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Use after free in Windows DNS allows an unauthorized attacker to deny service over a network.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

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
a network path → Use After Free → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
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-416 ↗

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

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

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

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's 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.
NetworkUnauthenticatedCWE-416
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-73321Official EUVD mapping

Use after free in Windows DNS allows an unauthorized attacker to deny service over a network.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3243Microsoft Windows: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in verschiedenen Versionen von Microsoft Windows Server, Microsoft Windows 10 und Microsoft Windows 11 ausnutzen, um seine Privilegien zu erhöhen, um einen Denial of Service herbeizuführen, um Informationen offenzulegen und um beliebigen Code auszuführen.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1147Multiples vulnérabilités dans Microsoft Windows

embre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78453 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78454 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78455 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78457 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78463 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78464 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78508 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78516 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-78523 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-80074 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-80075 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-80077 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-80083 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-80093 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-80096 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-81354 du 08 septembre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-81355 du 08 septembre 2026 Bulletin de sécurité Microso

Official advisory ↗
CSIRT Italia · Italian · aggiornamenti-mensili-microsoft-24Aggiornamenti Mensili Microsoft

nuova finestra - - CVE-2026-78510 : apre una nuova finestra - - CVE-2026-78511 : apre una nuova finestra - - CVE-2026-78512 : apre una nuova finestra - - CVE-2026-78513 : apre una nuova finestra - - CVE-2026-78514 : apre una nuova finestra - - CVE-2026-81400 : apre una nuova finestra - - CVE-2026-83942 : apre una nuova finestra - - CVE-2026-83940 : apre una nuova finestra - - CVE-2026-81401 : apre una nuova finestra - - CVE-2026-83941 : apre una nuova finestra - - CVE-2026-78526 : apre una nuova finestra - - CVE-2026-78520 : apre una nuova finestra - - CVE-2026-78521 : apre una nuova finestra - - CVE-2026-78522 : apre una nuova finestra - - CVE-2026-78523 : apre una nuova finestra - - CVE-2026-78524 : apre una nuova finestra - - CVE-2026-78525 : apre una nuova finestra - - CVE-2026-84000 : apre una nuova finestra - - CVE-2026-84001 : apre una nuova finestra - - CVE-2026-84003 : apre una nuova finestra - - CVE-2026-81378 : apre una nuova finestra - - CVE-2026-83711 : apre una nuova finestra - - CVE-2026-81377 : apre una nuova finestra - - CVE-2026-83954 : apre una nuova finestra - - CVE-2026-81376 : apre una nuova finestra - - CVE-2026-83955 : apre una nuova finestra - - CVE-2026-83951 : apre una nuova finestra - - CVE-2026-81379 : apre una nuova finestra - - CVE-2026-83952 : apre una nuova fi

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-033164マイクロソフトのMicrosoft Windows 10 1607等の複数製品における解放済みメモリの使用に関する脆弱性

Windows DNSにおけるUse after freeの脆弱性により、不正な攻撃者がネットワークを介してサービス拒否を引き起こす可能性があります。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6946MS 9월 보안 위협에 따른 정기 보안 업데이트 권고

취약성 | | Microsoft Office Excel | CVE-2026-78515 | Microsoft Office Excel 정보 유출 취약성 | | Windows Storage | CVE-2026-78516 | Windows 저장소 정보 유출 취약성 | | Microsoft Office Word | CVE-2026-78517 | Microsoft Office Word 원격 코드 실행 취약성 | | Microsoft Office Excel | CVE-2026-78518 | Microsoft Office Excel 원격 코드 실행 취약성 | | Microsoft Office Outlook | CVE-2026-78519 | Microsoft Office Outlook 원격 코드 실행 취약성 | | Microsoft Office Outlook | CVE-2026-78520 | Microsoft Office Outlook 정보 유출 취약성 | | Microsoft Office Word | CVE-2026-78521 | Microsoft Office Word 원격 코드 실행 취약성 | | Microsoft Office Word | CVE-2026-78522 | Microsoft Office Word 정보 공개 취약성 | | Windows DNS | CVE-2026-78523 | Windows DNS 서버 서비스 거부 취약성 | | Microsoft Office | CVE-2026-78524 | Microsoft Office 원격 코드 실행 취약성 | | Microsoft Office Outlook | CVE-2026-78525 | Microsoft Office Outlook 원격 코드 실행 취약성 | | Microsoft Office Word | CVE-2026-78526 | Microsoft Office Word 원격 코드 실행 취약성 | | Microsoft Office Outlook | CVE-2026-80073 | Microsoft Office Outlook 정보 유출 취약성 | | Remote Desktop Client | CVE-2026-80074 | 원격 데스크톱 클라이언트 원격 코드 실행 취약성 | | Windows Work Folders | CVE-2026-80075 | Windows Work Folders 권한 상승 취약성 | | Microsoft Office | CVE-2026-80076 | Microsoft Office 정보 유출 취약성 | | Remote Desktop Client | CVE-2026-80077 | 원격 데스크톱 클라이언트 원격 코드 실행 취약성 | | Microsoft Of

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. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 8 Sept 2026 · Last source change 1 Oct 2026, 22:55 UTC · CWE-416 · Use After Free

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-09
European sourceENISA EUVD · EUVD-2026-73321
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceOther authority
NVD statusNVD enriched

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    Windows 10 Version 1607: 10.0.14393.0 < 10.0.14393.9512; Windows 10 Version 1809: 10.0.17763.0 < 10.0.17763.9245; Windows Server 2012: 6.2.9200.0 < 6.2.9200.26349; Windows Server 2012 (Server Core installation): 6.2.9200.0 < 6.2.9200.26349; Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.23397; Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.23397; Windows Server 2016: 10.0.14393.0 < 10.0.14393.9512; Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.9512; Windows Server 2019: 10.0.17763.0 < 10.0.17763.9245; Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.9245; Windows Server 2022: 10.0.20348.0 < 10.0.20348.5622; Windows Server 2025: 10.0.26100.0 < 10.0.26100.33438; Windows Server 2025 (Server Core installation): 10.0.26100.0 < 10.0.26100.33438 · 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.
    After
    Windows 10 Version 1607: 10.0.14393.0 < 10.0.14393.9512; Windows 10 Version 1809: 10.0.17763.0 < 10.0.17763.9245; Windows Server 2012: 6.2.9200.0 < 6.2.9200.26349; Windows Server 2012 (Server Core installation): 6.2.9200.0 < 6.2.9200.26349; Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.23398; Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.23398; Windows Server 2016: 10.0.14393.0 < 10.0.14393.9512; Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.9512; Windows Server 2019: 10.0.17763.0 < 10.0.17763.9245; Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.9245; Windows Server 2022: 10.0.20348.0 < 10.0.20348.5622; Windows Server 2025: 10.0.26100.0 < 10.0.26100.33438; Windows Server 2025 (Server Core installation): 10.0.26100.0 < 10.0.26100.33438 · 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.
    CNA ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    10.0.14393.0 < 10.0.14393.9512; 10.0.17763.0 < 10.0.17763.9245; 6.2.9200.0 < 6.2.9200.26349; 6.3.9600.0 < 6.3.9600.23397 · 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.
    After
    Windows 10 Version 1607: 10.0.14393.0 < 10.0.14393.9512; Windows 10 Version 1809: 10.0.17763.0 < 10.0.17763.9245; Windows Server 2012: 6.2.9200.0 < 6.2.9200.26349; Windows Server 2012 (Server Core installation): 6.2.9200.0 < 6.2.9200.26349; Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.23397; Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.23397; Windows Server 2016: 10.0.14393.0 < 10.0.14393.9512; Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.9512; Windows Server 2019: 10.0.17763.0 < 10.0.17763.9245; Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.9245; Windows Server 2022: 10.0.20348.0 < 10.0.20348.5622; Windows Server 2025: 10.0.26100.0 < 10.0.26100.33438; Windows Server 2025 (Server Core installation): 10.0.26100.0 < 10.0.26100.33438 · 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.
    CNA ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: added patch: msrc.microsoft.com/CVE-2026-78523; added remediation: msrc.microsoft.com/CVE-2026-78523.
    Before
    no authoritative guidance recorded
    After
    patch: msrc.microsoft.com/CVE-2026-78523 · remediation: msrc.microsoft.com/CVE-2026-78523
    secure@microsoft.com ↗
  4. Affected versionsThe structured affected or fixed version information changed.
    Before
    10.0.14393.0 < 10.0.14393.9512; 10.0.17763.0 < 10.0.17763.9245; 6.2.9200.0 < 6.2.9200.26349; 6.3.9600.0 < 6.3.9600.23397 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    10.0.14393.0 < 10.0.14393.9512; 10.0.17763.0 < 10.0.17763.9245; 6.2.9200.0 < 6.2.9200.26349; 6.3.9600.0 < 6.3.9600.23397 · 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.
    CNA ↗
  5. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    secure@microsoft.com ↗
  6. ENISA EUVD mappingEUVD-2026-73321 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-73321"}
    ENISA EUVD ↗
  7. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
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-2026-73321↗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-2026-78523 · cve.blacktree.nl