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Microsoft SharePoint Server CVE-2026-105719

| EUVDEUVD-2026-99073 MEDIUM
Improper Input Validation (CWE-20)
2026-10-13 secure@microsoft.com GHSA-whmw-7r3h-8xrq
6.5
CVSS 3.1 · Vendor: microsoft
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain low-privilege SharePoint credentials
  2. Exploit
    Send crafted request over network
  3. Execution
    Trigger improper input validation flaw
  4. Impact
    Read unauthorized sensitive data

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
Exploitation Conditions

Exploitation requires a valid low-privilege authenticated session against Microsoft SharePoint Server Subscription Edition (versions 16.0.0 prior to 16.0.20326.20190), consistent with PR:L in the CVSS vector - it is NOT exploitable by fully unauthenticated attackers. The attacker crafts input that the server fails to validate properly (CWE-20) to disclose information. Limiting factors: the requirement for prior authentication (even if low-privilege) and the confidentiality-only impact (no integrity or availability effect) reduce realistic risk; the server must be network-reachable to the attacker. No special non-default configuration is named in the description.

Impact

This is a moderate-priority information disclosure vulnerability (CVSS 6.5) in Microsoft SharePoint Server Subscription Edition, not a top-tier emergency. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N indicates network-reachable, low-complexity exploitation requiring low-level authentication (PR:L), no user interaction, with high confidentiality impact but zero integrity or availability impact. No EPSS score, SSVC decision data, or POC evidence was provided in the input, and the CVE is not listed in CISA KEV, so there is no signal of active or widespread exploitation at this time. The signals are internally consistent - there is no network-vs-local or auth conflict - but the key risk-prioritization inputs (EPSS exploitation probability and SSVC automatable/exploitation status) are MISSING, so real-world exploitation likelihood cannot be quantified from the data provided. Because exploitation requires an already-authenticated (low-privilege) foothold and yields only read access, this leans toward a post-authentication data-leak issue rather than a pre-auth critical, but the high deployment footprint of SharePoint in enterprises warrants timely patching.

Exploit ScenarioDerived

A low-privileged authenticated user (or an attacker who has obtained valid low-privilege SharePoint credentials, e.g., via phishing) sends crafted requests over the network to the SharePoint server, abusing improper input validation (CWE-20) to read information they should not be able to access. No user interaction and only low privileges are required per the CVSS vector, but no public exploit code was identified in the provided data, so exploitation would require independent development.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 1.0% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 13, 2026

Improper input validation in Microsoft SharePoint Server Subscription Edition (versions 16.0.0 prior to 16.0.20326.20190) allows an attacker holding a valid low-privilege authenticated session to disclose confidential information over the network, with a CVSS 3.1 base score of 6.5. Because the vector is AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N, the weakness is remotely reachable and trivially triggered once a session exists, but it cannot be exploited by a fully unauthenticated attacker and produces no integrity or availability impact. There is no public exploit identified at time of analysis and no CISA KEV listing, so this is a moderate-priority patch-and-monitor item rather than an emergency, though the high confidentiality rating means successful abuse could expose content the attacker is not entitled to read, and the affected server must be network-accessible to the attacker for exploitation.

RemediationAI

Vendor-released patch: upgrade Microsoft SharePoint Server Subscription Edition to build 16.0.20326.20190 or later; the fix is available from the vendor and the definitive installation guidance and download links are in the MSRC advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-105719. Apply the cumulative update through the standard SharePoint patching workflow (run the installer on each farm server, then run the SharePoint Products Configuration Wizard), and verify the resulting build number afterwards, since the patch is delivered as a build-level cumulative update and a partial farm upgrade can leave servers inconsistent. If immediate patching is not possible, compensating controls should be chosen with their trade-offs in mind: restrict who can obtain authenticated sessions and trim site collection and web application permissions so PR:L exposure is limited to the smallest population (costs administrative effort and may disrupt legitimate collaboration); place the SharePoint front end behind an authenticated reverse proxy or VPN so only trusted networks can reach it (reduces external exposure but breaks external sharing and mobile access); and enable audit logging on document libraries and search/REST endpoints so anomalous data retrieval by low-privilege accounts can be detected (adds log volume and storage overhead without preventing exploitation). Because the impact is confidentiality-only and requires prior authentication, aggressive blocking of legitimate content access is generally not warranted, but monitoring for unusual read patterns from low-privilege accounts is a reasonable interim measure. There is no public exploit identified at time of analysis, so patching can follow a normal change window rather than an emergency process.

Affected VersionsENISA

Microsoft SharePoint Server Subscription Edition 16.0.0 <16.0.20326.20190

Affected Packages

euvd microsoft_sharepoint_server_subscription_edition fix: 16.0.20326.20190

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause class is CWE-20, improper input validation, in Microsoft SharePoint Server Subscription Edition, the subscription-based on-premises release of SharePoint whose build numbers track the 16.0.x line. SharePoint is an ASP.NET-based collaboration platform whose web front end accepts user-supplied input through forms, list operations, REST/CSOM endpoints, web parts, and query parameters, then mediates access to content stored in its content database. When input reaching one of these surfaces is not validated or normalized correctly, the server can be induced to return data outside the caller's intended authorization scope, yielding a confidentiality-only disclosure rather than code execution or tampering. The assessed CVSS vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N maps precisely onto that behavior: network attack vector, low attack complexity, low privileges required (a valid authenticated session, consistent with PR:L), no user interaction, unchanged scope, high confidentiality impact, and no integrity or availability impact. The weakness is present in Microsoft SharePoint Server Subscription Edition builds earlier than 16.0.20326.20190; adjacent SharePoint products such as Server 2016 and 2019 are not listed as affected by the available EUVD data, so affected-version scoping should be verified against the MSRC update guide before broad patching.

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Severity by source

Vendor (microsoft) PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
ENISA EUVD HIGH
vuln.today AI 6.5 MEDIUM

Network-reachable (AV:N) low-complexity attack needing a low-privilege authenticated session (PR:L); improper input validation leaks data, so C:H with no integrity or availability impact.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

2
Patch available
Oct 13, 2026 - 20:20 EUVD
CVE Published
Oct 13, 2026 - 19:17 nvd
MEDIUM 6.5

DescriptionCVE.org

Improper input validation in Microsoft Office SharePoint allows an authorized attacker to disclose information over a network.

Threat Intelligence Overview

EPSS Score
1.0%
Top 39% exploitable
Prevalence
High
SharePoint Server is widely deployed enterprise collaboration software
Threat Intel
1
1 sources
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Less Likely
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 1.0%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: +5

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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