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Full vulnerability report · 2026
CVE-2026-85324High confidence

Active Directory Federation Services (AD FS) Denial of Service Vulnerability

Microsoft · Windows 10 Version 1607

7.5HighCVSS 3.1
Recommended action
Within 7 days

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

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, 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 0.77% 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: Within 30 daysRemediation target: Within 180 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-2026-99464

No EUVD known-exploited evidence

Memory allocation with excessive size value in Active Directory Federation Services (AD FS) 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
7.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

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

Patch available
01

What, why and how

Memory allocation with excessive size value in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.

What

Memory allocation with excessive size value in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.

Why

The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.

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

Memory allocation with excessive size value in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.

Why

The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.

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 → Memory Allocation with Excessive Size Value → 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
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-789 ↗

CWE-789: Memory Allocation with Excessive Size Value. The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.

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:L/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.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.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-789
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-99464Official EUVD mapping

Memory allocation with excessive size value in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3892Microsoft Windows und Windows Server: Mehrere Schwachstellen

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in verschiedenen Versionen von Microsoft Windows Server und Microsoft Windows ausnutzen, um seine Privilegien auf administrative Rechte zu erhöhen, um beliebigen Code auszuführen, um Informationen offenzulegen, um einen Denial of Service herbeizuführen, um den Benutzer zu täuschen und andere, nicht näher spezifizierte Auswirkungen zu verursachen.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1314Avis du CERT-FR

6-84018 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-84019 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-84020 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85318 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85319 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85320 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85321 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85322 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85323 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85324 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85327 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85328 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85329 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85331 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85332 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85333 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85334 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-2026-85336 du 13 octobre 2026 Bulletin de sécurité Microsoft Windows CVE-202

Official advisory ↗
CSIRT Italia · Italian · aggiornamenti-mensili-microsoft-25Aggiornamenti Mensili Microsoft

nuova finestra - - CVE-2026-85354 : apre una nuova finestra - - CVE-2026-85353 : apre una nuova finestra - - CVE-2026-85352 : apre una nuova finestra - - CVE-2026-85343 : apre una nuova finestra - - CVE-2026-85342 : apre una nuova finestra - - CVE-2026-85341 : apre una nuova finestra - - CVE-2026-85340 : apre una nuova finestra - - CVE-2026-85339 : apre una nuova finestra - - CVE-2026-85338 : apre una nuova finestra - - CVE-2026-85334 : apre una nuova finestra - - CVE-2026-85332 : apre una nuova finestra - - CVE-2026-85329 : apre una nuova finestra - - CVE-2026-85328 : apre una nuova finestra - - CVE-2026-85327 : apre una nuova finestra - - CVE-2026-85324 : apre una nuova finestra - - CVE-2026-85322 : apre una nuova finestra - - CVE-2026-85321 : apre una nuova finestra - - CVE-2026-85319 : apre una nuova finestra - - CVE-2026-85318 : apre una nuova finestra - - CVE-2026-84020 : apre una nuova finestra - - CVE-2026-84019 : apre una nuova finestra - - CVE-2026-84018 : apre una nuova finestra - - CVE-2026-84017 : apre una nuova finestra - - CVE-2026-84016 : apre una nuova finestra - - CVE-2026-84015 : apre una nuova finestra - - CVE-2026-84014 : apre una nuova finestra - - CVE-2026-84013 : apre una nuova finestra - - CVE-2026-84012 : apre una nuova finestra - - CVE-2026-84008 : apre una nuova fi

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.
Official vendor articles6 stored documents

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

04

Evidence and provenance

Published 13 Oct 2026 · Last source change 14 Oct 2026, 17:51 UTC · CWE-789 · Memory Allocation with Excessive Size Value

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 2026-10-14
European sourceENISA EUVD · EUVD-2026-99464
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceOther authority
NVD statusNVD awaiting enrichment

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: acn.gov.it/aggiornamenti-mensili-microsoft-25.
    Before
    remediation: acn.gov.it/aggiornamenti-mensili-microsoft-25
    After
    no authoritative guidance recorded
    CNA ↗
  2. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    CNA ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: acn.gov.it/aggiornamenti-mensili-microsoft-25.
    Before
    remediation: acn.gov.it/aggiornamenti-mensili-microsoft-25
    After
    no authoritative guidance recorded
    CNA ↗
  4. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    CNA ↗
  5. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    CSIRT Italia ↗
  6. ENISA EUVD mappingEUVD-2026-99464 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-99464"}
    ENISA EUVD ↗
  7. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
  8. CVSS scoreCVSS vector changed while the displayed base score remained 7.5.
    Before
    7.5 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
    After
    7.5 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Remediation guidance recorded
ENISA EUVD · EUVD-2026-99464↗CSIRT Italia remediation guidance↗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-2026-85324 · cve.blacktree.nl