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Full vulnerability report · 2026
CVE-2026-20945High confidence

Microsoft SharePoint Server Spoofing Vulnerability

Microsoft · Microsoft SharePoint Enterprise Server 2016

4.6MediumCVSS 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 19.07% 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 Microsoft SharePoint Enterprise Server 2016 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-2026-22355

No EUVD known-exploited evidence

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing 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
4.6 · 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

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.

What

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.

Why

Attacker-controlled content can reach a browser as executable script without sufficient output encoding or sanitisation.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.

Why

Attacker-controlled content can reach a browser as executable script without sufficient output encoding or sanitisation.

How

An attacker operating through a network path may attempt exploitation with low privileges. 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 → Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
Required interaction required
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-79 ↗

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'). The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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:L/UI:R/S:U/C:L/I:L/A:N/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.PRLowPrivileges required: The attacker needs basic user-level privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
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.
NetworkCWE-79
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-22355Official EUVD mapping

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.

Official EUVD record ↗
BSI · German · WID-SEC-2026-1102Microsoft Office: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Microsoft Excel, Microsoft PowerPoint, Microsoft Office, Microsoft Office Online Server, Microsoft SharePoint, Microsoft SharePoint Server 2019 und Microsoft 365 Apps ausnutzen, um beliebigen Programmcode auszuführen, Spoofing-Angriffe durchzuführen, Daten zu manipulieren und vertrauliche Informationen offenzulegen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260415Security Bulletin 15 April 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 15 April 2026, published on 15 April 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0445Multiples vulnérabilités dans les produits Microsoft

De multiples vulnérabilités ont été découvertes dans les produits Microsoft. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, une élévation de privilèges et un déni de service à distance. Microsoft indique que la vulnérabilité CVE-2026-32201 est activement exploitée.

Official advisory ↗
CSIRT Italia · Italian · aggiornamenti-mensili-microsoft-19Aggiornamenti Mensili Microsoft

nuova finestra - - CVE-2026-26159 : apre una nuova finestra - - CVE-2026-26156 : apre una nuova finestra - - CVE-2026-26155 : apre una nuova finestra - - CVE-2026-26154 : apre una nuova finestra - - CVE-2026-26153 : apre una nuova finestra - - CVE-2026-26152 : apre una nuova finestra - - CVE-2026-26151 : apre una nuova finestra - - CVE-2026-26149 : apre una nuova finestra - - CVE-2026-26143 : apre una nuova finestra - - CVE-2026-25184 : apre una nuova finestra - - CVE-2026-23670 : apre una nuova finestra - - CVE-2026-23666 : apre una nuova finestra - - CVE-2026-23657 : apre una nuova finestra - - CVE-2026-23653 : apre una nuova finestra - - CVE-2026-20945 : apre una nuova finestra - - CVE-2026-20930 : apre una nuova finestra - - CVE-2026-20928 : apre una nuova finestra - - CVE-2026-20806 : apre una nuova finestra - - CVE-2026-0390 : apre una nuova finestra - - Riferimenti (2) https://msrc.microsoft.com/update-guide/releaseNote/2026-apr https://msrc.microsoft.com/update-guide Change log Titolo della tabella Versione Note Data 1.0 Pubblicato il 15-04-2026 15/04/2026 1.1 Aggiornata la sezione "CVE" con presenza PoC per la CVE-2026-32196 17/04/2026 1.2 Aggiornata la sezione "CVE" per rilevato sfruttamento della CVE-2026-33825 23/04/2026 1.3 Aggiornata sezione "CVE" per rilevato sfruttamento della

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-014424マイクロソフトのMicrosoft SharePoint Serverにおけるクロスサイトスクリプティングの脆弱性

Microsoft Office SharePoint におけるウェブページ生成時の入力が不適切に中和される（クロスサイトスクリプティング）ため、認可された攻撃者がネットワークを介してなりすましを行うことが可能です。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6760MS 4월 보안 위협에 따른 정기 보안 업데이트 권고

soft.com/update-guide/ko-kr/ [2] (영문) https://msrc.microsoft.com/update-guide/en-us/ [3] https://msrc.microsoft.com/update-guide/releaseNote/2026-Apr o 취약점 요약 정보 (총 247개) | 제품 카테고리 | CVE 번호 | CVE 제목 | |:---:|:---:|:---:| | Windows 재부팅 로더 | CVE-2026-0390 | Windows Boot Loader Security Feature Bypass Vulnerability | | Windows COM | CVE-2026-20806 | Windows COM Information Disclosure Vulnerability | | Windows 복구 환경 에이전트 | CVE-2026-20928 | Windows Recovery Environment Agent Security Feature Bypass Vulnerability | | Windows 서비스 관리 | CVE-2026-20930 | Windows Management Services Elevation of Privilege Vulnerability | | Microsoft Office SharePoint | CVE-2026-20945 | Microsoft Office SharePoint Spoofing Vulnerability | | GitHub Copilot 및 Visual Studio Code | CVE-2026-23653 | GitHub Copilot and Visual Studio Code Information Disclosure Vulnerability | | 마이크로소프트 오피스 워드 | CVE-2026-23657 | Microsoft Office Word Remote Code Execution Vulnerability | | .NET 프레임워크 | CVE-2026-23666 | .NET Framework Denial of Service Vulnerability | | Windows VBS(가상화 기반 보안) 엔클레이브 | CVE-2026-23670 | Windows Virtualization-Based Security (VBS) Enclave Security Feature Bypass Vulnerability | | Applocker 핀드라이버(applockerfltr.sys) | CVE-2026-25184 | Applocker (applockerfltr.sys) Elevation of Privilege Vulnerability | | Microsoft Powe

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0116Kwetsbaarheden verholpen in Microsoft Office

Een kwaadwillende kan de kwetsbaarheden misbruiken om beveiligingsmaatregelen te omzeilen, zoch voor te doen als andere gebruiker en zich zo verhoogde rechten toe te kennen en toegang te krijgen tot gevoelige gegevens. Voor succesvol misbruik moet de kwaadwillende het slachtoffer misleiden en malafide bestand te openen of link te volgen. ``` Microsoft Office PowerPoint: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-32200 | 7,80 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| Microsoft Office Word: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-33095 | 7,80 | Uitvoeren van willekeurige code | | CVE-2026-33822 | 6,10 | Toegang tot gevoelige gegevens | | CVE-2026-23657 | 7,80 | Uitvoeren van willekeurige code | | CVE-2026-33114 | 8,40 | Uitvoeren van willekeurige code | | CVE-2026-33115 | 8,40 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| Microsoft Office: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-32190 | 8,40 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| Microsoft Office SharePoint: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-20945 | 4,60 | Voordoen als andere gebruiker | | CVE-2026-32201 | 6,50 | Voordoen als andere gebruiker | |----------------|------|-------------------------------------| Microsoft Office Excel: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-32188 | 7,10 | Toegang tot gevoelige gegevens | | CVE-2026-32189 | 7,80 | Uitvoeren van willekeurige code | | CVE-2026-32197 | 7,80 | Uitvoeren van willekeurige code | | CVE-2026-32198 | 7,80 | Uitvoeren van willekeurige code | | CVE-2026-32199 | 7,80 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| ```

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 articles5 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 14 Apr 2026 · Last source change 15 Oct 2026, 15:52 UTC · CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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 2026-08-14
European sourceENISA EUVD · EUVD-2026-22355
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. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: acn.gov.it/aggiornamenti-mensili-microsoft-19.
    Before
    remediation: acn.gov.it/aggiornamenti-mensili-microsoft-19 · vendor advisory: msrc.microsoft.com/CVE-2026-20945
    After
    vendor advisory: msrc.microsoft.com/CVE-2026-20945
    secure@microsoft.com ↗
  2. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    secure@microsoft.com ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: acn.gov.it/aggiornamenti-mensili-microsoft-19.
    Before
    remediation: acn.gov.it/aggiornamenti-mensili-microsoft-19 · vendor advisory: msrc.microsoft.com/CVE-2026-20945
    After
    vendor advisory: msrc.microsoft.com/CVE-2026-20945
    secure@microsoft.com ↗
  4. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    secure@microsoft.com ↗
  5. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: acn.gov.it/aggiornamenti-mensili-microsoft-19.
    Before
    remediation: acn.gov.it/aggiornamenti-mensili-microsoft-19 · vendor advisory: msrc.microsoft.com/CVE-2026-20945
    After
    vendor advisory: msrc.microsoft.com/CVE-2026-20945
    secure@microsoft.com ↗
  6. Affected versionsThe structured affected or fixed version information changed.
    Before
    16.0.0 < 16.0.5548.1003; 16.0.0 < 16.0.10417.20114; 16.0.0 < 16.0.19725.20210 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Microsoft SharePoint Enterprise Server 2016: 16.0.0 < 16.0.5548.1003; Microsoft SharePoint Server 2019: 16.0.0 < 16.0.10417.20114; Microsoft SharePoint Server Subscription Edition: 16.0.0 < 16.0.19725.20210 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  7. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    secure@microsoft.com ↗
  8. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    CSIRT Italia ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Remediation guidance recorded
ENISA EUVD · EUVD-2026-22355↗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-2026-20945 · cve.blacktree.nl