CVE-2026-26105
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 · uneditedImproper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing 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 confidenceCross-site scripting (XSS) vulnerability in Microsoft Office SharePoint allows unauthorized attackers to inject malicious scripts into web pages viewed by other users, enabling session hijacking, credential theft, or content spoofing.
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< 16.0.19725.20076= 2016= 2019CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
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 checksWork through these to decide whether this CVE applies to you.
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Identify SharePoint Server versionOpen SharePoint Administration Center, go to System Settings > Manage servers in this farm, or run Get-SPFarm | Select BuildVersion in PowerShellAffected if The version shown is 2016, 2019, or a subscription version lower than 16.0.19725.20076
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Check if custom web parts accept user inputReview all custom or third-party web parts that accept and display user-provided content, including forms, comment sections, or search web partsAffected if Any web part accepts user input without proper server-side validation and output encoding is present
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Inspect SharePoint page rendering for user contentExamine SharePoint pages that display user-supplied data in lists, libraries, or content editor web parts using browser developer tools to view the HTML sourceAffected if User-supplied content is rendered directly to HTML without encoding, visible in the page source as raw input rather than encoded entities
Your SharePoint installation is affected if it is version 2016, 2019, or a subscription version below 16.0.19725.20076 and contains web parts or pages that render user input without validation and encoding.
Generated from the published advisory. Verify against your own configuration.
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 · scoped16.0.19725.20076
Apply Microsoft security patches for SharePoint when available; implement input validation and output encoding for all user-supplied data before rendering in browsers.
SharePoint Server 2016/2019 with cumulative update version 16.0.19725.20076 or later
- Verify current SharePoint Server version via SharePoint Administration Central > Farm Administration > Farm Products and Versions
- Download the cumulative update or security update containing version 16.0.19725.20076 from Microsoft Update Catalog or Microsoft Download Center
- Test the update in a non-production SharePoint farm environment before applying to production
- Back up the SharePoint farm configuration and content databases
- Run the SharePoint Products Configuration Wizard (psconfig.exe) after applying the update
- Verify the farm version is now 16.0.19725.20076 via SharePoint Administration or Get-SPFarm PowerShell cmdlet
- Validate that affected web applications are functioning correctly post-update
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,192.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-26105 — 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.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-26105 in production — separate from our analysis above.
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
No notes yet
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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.
- 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