dbcve.org
Sharepoint ServerApplication · Microsoft

CVE-2026-33112

HIGH · 8.8 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 16.0.19725.20280 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

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
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

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

Insecure deserialization vulnerability in Microsoft Office SharePoint enables authenticated attackers to execute arbitrary code remotely by exploiting untrusted data processed through deserialization routines.

MitigationApply Microsoft's latest SharePoint security updates and implement strict input validation on deserialization endpoints to block malicious payloads.

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:< 16.0.19725.20280= 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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/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.

  1. Verify SharePoint Server is installed
    Check for SharePoint installation by looking for SharePoint-related services or binaries. In PowerShell, run: Get-Service | Where-Object {$_.DisplayName -like '*SharePoint*'} or check for SharePoint Management Shell availability
    Affected if No SharePoint services found indicates the system is not affected
  2. Determine the installed SharePoint version
    Open SharePoint Management Shell and run: (Get-SPFarm).BuildVersion or check the registry key: HKLM:\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\16.0\SharePoint\Setup\Version
    Affected if Version cannot be determined via these methods indicates SharePoint may not be present or access is limited
  3. Compare installed version against affected ranges
    If version is retrieved, compare it to: versions below 16.0.19725.20280, or exactly version 2016, or exactly version 2019
    Affected if Installed version matches any of these three conditions (less than 16.0.19725.20280, or equals 2016, or equals 2019)
  4. Identify custom SharePoint solutions with deserialization
    Review any custom SharePoint solutions, web parts, or timer jobs for use of .NET deserialization (BinaryFormatter, SoapFormatter, or third-party serializers) that process untrusted data
    Affected if Custom solutions exist that deserialize untrusted or externally-supplied data without validation

A system is affected if it runs a vulnerable SharePoint Server version (2016, 2019, or any version below 16.0.19725.20280) and contains custom solutions or configurations that deserialize untrusted data.

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.

dbcve · scoped
Upgrade available Upgrade to 16.0.19725.20280 or later
Fixed in 16.0.19725.20280
Interim mitigation

Apply Microsoft's latest SharePoint security updates and implement strict input validation on deserialization endpoints to block malicious payloads.

Recommended fix Moderate confidence

SharePoint Server 2016/2019 to version 16.0.19725.20280 or later

  1. 1. Identify current SharePoint Server version by navigating to SharePoint Central Administration > System Settings > Manage farm servers
  2. 2. Download and apply the latest SharePoint Server update from Microsoft Update Catalog or Microsoft Download Center matching version 16.0.19725.20280 or later
  3. 3. Run SharePoint Products Configuration Wizard (PSConfig) on all servers in the farm after applying the update
  4. 4. Verify successful upgrade by checking the farm version in Central Administration matches the target patch version
  5. 5. Test critical SharePoint workflows and web applications to confirm functionality
Caveat Review Microsoft documentation for any prerequisite updates required before installing this patch (such as .NET Framework or Windows updates); test in non-production environment first as updates may affect custom solutions or third-party add-ins

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Sharepoint Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,616.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-33112 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-33112 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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