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CVE-2026-88201 Microsoft CVE debrief

Microsoft Office Excel Information Disclosure Vulnerability allows an unauthorized attacker to disclose information over a network due to a buffer over-read issue. This vulnerability affects Microsoft Office Excel deployments, which defenders should assess for exposure and apply patches to mitigate. The vulnerability has a medium severity and is identified as CVE-2026-88201. Defenders should prioritize verifying exposure in Microsoft Office Excel deployments and applying vendor patches.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
MEDIUM 6.5
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 Office Excel deployments should assess exposure and apply patches to mitigate CVE-2026-88201. This vulnerability affects Microsoft Office Excel and requires verification of exposure and application of vendor patches. Defenders should prioritize verifying exposure in Microsoft Office Excel deployments and applying vendor patches.

Why it matters

CVE-2026-88201 is a medium-severity vulnerability in Microsoft Office Excel that allows information disclosure over a network. Defenders should verify exposure, apply patches, and monitor for potential issues.

  • Potential information disclosure
  • Verification of exposure required
  • Patch application priority for Microsoft Office Excel deployments

Technical summary

A buffer over-read vulnerability in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network. This vulnerability, identified as CVE-2026-88201, affects Microsoft Office Excel deployments and requires defenders to assess exposure and apply patches. The vulnerability has a medium severity and is categorized as an information disclosure vulnerability.

Defensive priority

Defenders should prioritize verifying exposure in Microsoft Office Excel deployments and applying vendor patches.

Recommended defensive actions

  • Verify exposure in Microsoft Office Excel deployments
  • Apply vendor patches
  • Monitor for potential information disclosure

Evidence notes

The CVE record and source item provide details on the vulnerability, but limited information is available on exploitation or impact. Defenders should verify exposure, apply patches, and monitor for potential issues related to CVE-2026-88201. The CVE Program record and NIST NVD detail page offer official information on the vulnerability. Vendor advisory and patch information are also available.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-88201 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-88201

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

  • CVE-2026-88201 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-88201

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

Supplemental references

  • Microsoft Office Excel Information Disclosure Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/88xxx/CVE-2026-88201.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88201

    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.