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PatchSiren cyber security CVE debrief

CVE-2026-80089 Microsoft CVE debrief

Microsoft Office vulnerability CVE-2026-80089 allows unauthorized information disclosure over a network due to an out-of-bounds read issue. The vulnerability affects Microsoft Office deployments, particularly in enterprise environments, and requires defenders to assess exposure and prioritize patching. The CVE record and NVD entry provide details on the vulnerability, and Microsoft has released a patch advisory. Defenders should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-17
Advisory published
2026-09-08
Advisory updated
2026-09-17

Who should care

Defenders responsible for Microsoft Office deployments, particularly those in enterprise environments, should assess exposure and prioritize patching.

Why it matters

CVE-2026-80089 is a medium-severity vulnerability in Microsoft Office that requires defenders to assess exposure, prioritize patching, and monitor for potential information disclosure attempts.

  • Potential information disclosure over the network
  • Need to verify and patch vulnerable Office versions
  • Possible impact on business-critical systems using Office

Technical summary

CVE-2026-80089 is an out-of-bounds read vulnerability in Microsoft Office that allows an unauthorized attacker to disclose information over a network. The vulnerability has a CVSS score of 6.5 and is classified as MEDIUM severity. It affects Microsoft Office deployments, particularly in enterprise environments, and requires defenders to assess exposure and prioritize patching. The official CVE Program record and NVD entry provide source-provided CVE metadata and official NIST NVD detail page and source-specific vulnerability assessment.

Defensive priority

Assess exposure of Microsoft Office deployments, prioritize patching for enterprise and business-critical systems.

Recommended defensive actions

  • Inventory and assess exposure of Microsoft Office installations
  • Prioritize and apply patches for vulnerable Office versions
  • Monitor for potential information disclosure attempts

Evidence notes

The CVE record and NVD entry provide details on the vulnerability. Microsoft has released a patch advisory. The vulnerability has a CVSS score of 6.5 and is classified as MEDIUM severity. The CVE record was published on 2026-09-08T18:20:51.410Z and has not been modified since then. The official CVE Program record and NVD entry provide source-provided CVE metadata and official NIST NVD detail page and source-specific vulnerability assessment.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-80089 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-80089

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

  • CVE-2026-80089 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-80089

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

Supplemental references

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.