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PatchSiren cyber security CVE debrief

CVE-2026-45645 Microsoft CVE debrief

CVE-2026-45645 is a heap-based buffer overflow vulnerability in Microsoft Office. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. The vulnerability was published on 2026-06-09T17:17:31.667Z and last modified on 2026-06-09T19:32:51.440Z. The vendor of the affected product is currently listed as Unknown Vendor, but evidence suggests that the vendor may be Microsoft (see [reference_domain_candidate](https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-06-09T12%3A30%3A41.000Z&lastModEndDate=2026-06-11T01%3A46%3A21.000Z)). The vulnerability is described as allowing an unauthorized attacker to execute code locally.

Vendor
Microsoft
Product
Microsoft 365 Apps for Enterprise
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-07-09
Advisory published
2026-06-09
Advisory updated
2026-07-09

Who should care

Administrators and users of Microsoft Office should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The vulnerability is a heap-based buffer overflow in Microsoft Office. The CVSS vector for this vulnerability is CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Defensive priority

HIGH

Recommended defensive actions

  • Apply patches or updates from the vendor as they become available.
  • Use secure coding practices when developing applications.
  • Limit exposure by restricting access to vulnerable systems.

Evidence notes

The vendor is currently listed as Unknown Vendor, but evidence suggests that the vendor may be Microsoft.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45645 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45645

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

  • CVE-2026-45645 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45645

    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.