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PatchSiren cyber security CVE debrief

CVE-2026-100208 Microsoft CVE debrief

CVE-2026-100208 is an integer overflow or wraparound vulnerability in Microsoft Office Outlook that allows an unauthorized attacker to execute code over a network. The CVE record was published on 2026-09-25T20:17:04.760Z and has not been modified since then. The NVD entry is currently Received. Defenders should assess potential exposure and impact on Outlook deployments, focusing on verifying exposure, assessing potential impact, and monitoring for updates from Microsoft. This vulnerability has significant implications for organizations using Microsoft Office Outlook, as it could allow attackers to execute code remotely.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-25
Original CVE updated
2026-09-26
Advisory published
2026-09-25
Advisory updated
2026-09-26

Who should care

Defenders responsible for Microsoft Office Outlook deployments, security teams, and vulnerability management teams should assess potential exposure and impact. This includes verifying exposure, assessing potential impact on affected systems, and monitoring for updates from Microsoft. Prioritization should be given to deployments with high-risk exposure or those that are critical to organizational operations.

Why it matters

CVE-2026-100208 is an integer overflow or wraparound vulnerability in Microsoft Office Outlook that allows an unauthorized attacker to execute code over a network. Defenders should prioritize verifying exposure and assessing potential impact on Outlook deployments.

  • Verify exposure and assess potential impact on Outlook deployments
  • Monitor for updates from Microsoft
  • Assess impact on affected systems

Technical summary

CVE-2026-100208 is an integer overflow or wraparound vulnerability in Microsoft Office Outlook that allows an unauthorized attacker to execute code over a network. The vulnerability affects Microsoft Office Outlook and could allow attackers to execute code remotely, potentially leading to unauthorized access and control. Defenders should prioritize verifying exposure and assessing potential impact on Outlook deployments.

Defensive priority

Defenders should prioritize verifying exposure and assessing potential impact on Outlook deployments.

Recommended defensive actions

  • Verify Outlook deployments for potential exposure
  • Assess impact on affected systems
  • Monitor for updates from Microsoft

Evidence notes

The CVE record and NVD entry provide limited information about the vulnerability, and additional details may be required to fully assess exposure and impact.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-100208 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-100208

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

  • CVE-2026-100208 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-100208

    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.