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CVE-2026-88204 Microsoft CVE debrief

Microsoft Office SharePoint Spoofing Vulnerability allows an authorized attacker to perform spoofing over a network due to improper neutralization of input during web page generation. This vulnerability has a CVSS score of 7.3 and is classified as HIGH severity. The vulnerability affects Microsoft SharePoint Server Subscription Edition instances, specifically those with version 16.0.0 less than 16.0.20326.20190. Defenders responsible for these instances should assess exposure and prioritize patching. The CVE record and source item provide details on the vulnerability, its impact, and affected versions.

Vendor
Microsoft
Product
Microsoft SharePoint Server Subscription Edition
CVSS
HIGH 7.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-13
Original CVE updated
2026-10-13
Advisory published
2026-10-13
Advisory updated
2026-10-13

Who should care

Defenders responsible for Microsoft SharePoint Server Subscription Edition instances, specifically those with version 16.0.0 less than 16.0.20326.20190, should assess exposure and prioritize patching.

Why it matters

CVE-2026-88204 is a high-severity spoofing vulnerability in Microsoft Office SharePoint that requires verification and patching to prevent potential attacks. Defenders should prioritize patching and monitoring SharePoint Server Subscription Edition instances.

  • Verify and apply patches to prevent potential spoofing attacks
  • Review and update inventory of SharePoint Server Subscription Edition instances to ensure accurate tracking
  • Monitor for suspicious activity on SharePoint Server Subscription Edition instances to detect potential attacks

Technical summary

The vulnerability is due to improper neutralization of input during web page generation in Microsoft Office SharePoint, allowing an authorized attacker to perform spoofing over a network. The vulnerability affects Microsoft SharePoint Server Subscription Edition, specifically versions 16.0.0 less than 16.0.20326.20190. Defenders should prioritize verifying and applying patches for these affected versions.

Defensive priority

Defenders should prioritize verifying and applying patches for Microsoft SharePoint Server Subscription Edition, specifically for versions 16.0.0 less than 16.0.20326.20190.

Recommended defensive actions

  • Verify and apply patches for Microsoft SharePoint Server Subscription Edition
  • Review and update inventory of SharePoint Server Subscription Edition instances
  • Monitor for suspicious activity on SharePoint Server Subscription Edition instances

Evidence notes

The CVE record and source item provide details on the vulnerability, its impact, and affected versions. However, there is limited information on potential exploits or attacks.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-88204 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-88204

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-88204 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-88204

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Microsoft Office SharePoint Spoofing Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/88xxx/CVE-2026-88204.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88204

    Supplemental source - vendor-advisory, patch

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.