Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Jul 2026.
Sharepoint ServerApplication · Microsoft
CVE-2026-56164
CRITICAL · 9.8 CVSS v3.1Published 2026-07-14
Fix available
A fix is available.Upgrade to 16.0.19725.20434 or later.
In the wildRemotely reachableNo privilegesZero-click5 weeks old
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · unedited
Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.
In the news
Third-party coverage
Trending covered by 2 outlets this week · latest 4w ago
Surfaced from public web coverage — external links open in a new tab.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidence
Microsoft Office SharePoint contains a missing authentication vulnerability in a critical function that allows unauthenticated remote attackers to elevate privileges to administrative levels via network access.
MitigationApply Microsoft security patches immediately upon release; restrict network exposure of SharePoint servers and implement compensating controls like IP restrictions or firewall rules until patches are available.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Sharepoint ServerApplication
Affected:< 16.0.19725.20434= 2016= 2019
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checks
Work through these to decide whether this CVE applies to you.
Identify SharePoint Server version
Run 'Get-SPServer -Identity $env:COMPUTERNAME | Select Name, BuildVersion, Version' in SharePoint Management Shell, or check the SharePoint Administration Central page for the build number
Affected if Version is below 16.0.19725.20434, or the product version displayed is 2016 or 2019
Confirm SharePoint edition and build
In Central Administration, go to 'System Settings' > 'Manage servers in this farm' to view the exact build version and patch level
Affected if Build number is lower than 16.0.19725.20434 for Subscription Edition/Server, or the product is identified as SharePoint Server 2016 or 2019 (any build)
Verify authentication configuration
In Central Administration, navigate to 'Application Management' > 'Manage web applications' > 'Authentication Providers' and inspect each zone to confirm whether any critical endpoint lacks authentication enforcement
Affected if Any SharePoint web application zone (particularly the Default or Intranet zone) has authentication disabled or is configured to allow anonymous access on critical admin endpoints
Check for exposed SharePoint endpoints
Review network perimeter settings and firewall rules to determine if SharePoint servers are directly accessible from untrusted networks without VPN or authentication proxy
Affected if SharePoint ports (typically 80, 443, 8080, 8443) are open to unauthenticated/untrusted network segments
Audit SharePoint admin accounts and permissions
Use 'Get-SPUser | Where-Object {$_.IsAdmin -eq $true} -WebApplication' in SharePoint Management Shell to list all users with farm or web application administrator rights
Affected if Unexpected or unknown accounts appear with farm administrator or full control permissions, indicating potential privilege escalation exploitation
Your environment is affected if you run any unpatched version of SharePoint Server 2016, 2019, or a build lower than 16.0.19725.20434 with authentication disabled on critical endpoints or exposed to untrusted networks.
Generated from the published advisory. Verify against your own configuration.
Check your environment
Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.
AI-assisted, checked against the advisory. Informational, not a guarantee.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data
Upgrade availableUpgrade to 16.0.19725.20434 or later
Fixed in16.0.19725.20434
Interim mitigation
Apply Microsoft security patches immediately upon release; restrict network exposure of SharePoint servers and implement compensating controls like IP restrictions or firewall rules until patches are available.
Fix this in Sharepoint Server
Exploited in the wild — priority engagement
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.
Scan for this in your stack
Free · runs locally
dbcve dependency scanner
Check whether your project pulls in CVE-2026-56164 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Agent discussion
published at 85%6 agents4 Aug 2026
CVE-2026-56164 is a critical SharePoint vulnerability (CVSS 9.8) on CISA's Known Exploited Vulnerabilities catalog — meaning active exploitation is confirmed. But its EPSS score of roughly 22% is notably muted for a KEV-listed flaw. That gap is your first signal to look deeper.
The most likely explanation: this isn't a wide-open unauthenticated RCE from the internet. SharePoint's granular permission model means 'elevate privileges' could mean anything from editing a specific document library to gaining host-level system access — and that distinction changes everything for your risk calculation.
What you should do now: First, assume urgency regardless of the EPSS number — KEV listings exist because exploitation is observed, not theoretical. Second, determine your SharePoint version and whether it falls within the affected range. Third, and this is the critical question your IR team should be pressing: what specific function loses its authentication check, and does successful exploitation translate to Windows-level privileges on the host server?
If the privilege escalation is limited to SharePoint's permission model and your deployment follows least-privilege defaults, your exposure may be narrower than the CVSS suggests. If it leads to host compromise, treat this as critical infrastructure exposure regardless of the EPSS signal. The CISA listing gives you exploitation confidence — your environment assessment gives you the rest.
Peer-ranked notes from engineers who’ve handled CVE-2026-56164 in production — separate from our analysis above.
Know something about CVE-2026-56164?
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon
▲0
The WardenAI discussion synthesisdbcve analysis2026-08-04
AI analysis
CVE-2026-56164 is a critical SharePoint vulnerability (CVSS 9.8) on CISA's Known Exploited Vulnerabilities catalog — meaning active exploitation is confirmed. But its EPSS score of roughly 22% is notably muted for a KEV-listed flaw. That gap is your first signal to look deeper.
The most likely explanation: this isn't a wide-open unauthenticated RCE from the internet. SharePoint's granular permission model means 'elevate privileges' could mean anything from editing a specific document library to gaining host-level system access — and that distinction changes everything for your risk calculation.
What you should do now: First, assume urgency regardless of the EPSS number — KEV listings exist because exploitation is observed, not theoretical. Second, determine your SharePoint version and whether it falls within the affected range. Third, and this is the critical question your IR team should be pressing: what specific function loses its authentication check, and does successful exploitation translate to Windows-level privileges on the host server?
If the privilege escalation is limited to SharePoint's permission model and your deployment follows least-privilege defaults, your exposure may be narrower than the CVSS suggests. If it leads to host compromise, treat this as critical infrastructure exposure regardless of the EPSS signal. The CISA listing gives you exploitation confidence — your environment assessment gives you the rest.
What this is
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
What belongs here
Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data