BlackTreeIndependent security intelligence
← Back to the CVE catalogue
Full vulnerability report · 2026
CVE-2026-32201High confidence

Microsoft SharePoint Server Improper Input Validation Vulnerability

Microsoft · SharePoint Server

6.5MediumCVSS 3.1
Recommended action
Protect now

CISA confirms exploitation in the wild and lists 2026-04-28 as the remediation due date.

Fix not verified
Optional official sources

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

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

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-2026-22587

CISA KEV mirrored by ENISA

Improper input validation in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 14 Apr 2026. Evidence sources: cisa_kev.
ENISA score
6.5 · CVSS 3.1
Advisory evidence
2 linked advisory records
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_ncscnl · NCSC-2026-0116Kwetsbaarheden verholpen in Microsoft Office
Recommended actionProtect now

CISA confirms exploitation in the wild and lists 2026-04-28 as the remediation due date.

Fix not verified
01

What, why and how

Microsoft SharePoint Server contains an improper input validation vulnerability that allows an unauthorized attacker to perform spoofing over a network.

What

Microsoft SharePoint Server contains an improper input validation vulnerability that allows an unauthorized attacker to perform spoofing over a network.

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 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

Microsoft SharePoint Server contains an improper input validation vulnerability that allows an unauthorized attacker to perform spoofing over a network.

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 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.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-04-14.

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 Input Validation → 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-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:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:F/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.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.
NetworkUnauthenticatedCWE-20CISA KEV
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-22587Known-exploited evidence recorded

Improper input validation in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

Official EUVD record
BSI · German · WID-SEC-W-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
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

Aggiornamenti Mensili Microsoft Aggiornamenti Mensili Microsoft Alert AL02/260415/CSIRT-ITA Condividi Facebook Twitter LinkedIn Whatsapp Sintesi Microsoft ha rilasciato gli aggiornamenti di sicurezza mensili che risolvono un totale di 165 nuove vulnerabilità, di cui due di tipo 0-day. Tipologia Denial of Service Elevation of Privilege Information Disclosure Remote Code Execution Security Feature Bypass Spoofing Tampering Descrizione e potenziali impatti Nel dettaglio le vulnerabilità sfruttate attivamente o per le quali risulta disponibile in rete anche un “proof of concept”, riguardano: Microsoft SharePoint Server : identificata tramite la CVE-2026-32201, di tipo “ Spoofing ” e con score CVSS v3.1 pari a 6.5, interessa le istanze Microsoft SharePoint Server ed è causata da un’inadeguata validazione dell’input ( Improper Input Validation ). Nel dettaglio, un attaccante potrebbe sfruttare tale vulnerabilità per impersonare un’entità legittima sui sistemi target. Microsoft Defender Antimalware Platform: questo CSIRT ha analizzato e testato la CVE-2026-33825, nota con il nome di “BlueHammer”, di tipo “ Elevation of Privilege ” e con score CVSS v3.1 pari a 7.8, che interessa Microsoft Defender Antimalware Platform. In dettaglio, è stato verificato che la vulnerabilità è riconducibile a una condiz

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

Microsoft Office SharePoint suffers from an improper input validation vulnerability that enables unauthorized attackers to perform network spoofing.

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.
Fix not verified
Affected
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.
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. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 14 Apr 2026 · Last source change 14 Aug 2026, 16:31 UTC · CWE-20 · Improper Input Validation

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-2026-22587
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. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
ENISA EUVD · EUVD-2026-22587↗CISA KEV record↗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-2026-32201 · cve.blacktree.nl