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CVE-2026-45484 Microsoft CVE debrief

CVE-2026-45484 is a HIGH severity vulnerability in Microsoft Office SharePoint, with a CVSS score of 8.8. The vulnerability is caused by deserialization of untrusted data, allowing an authorized attacker to elevate privileges over a network. The CVE was published on 2026-06-09T17:17:22.883Z and last modified on 2026-06-09T19:32:51.440Z.

Vendor
Microsoft
Product
Microsoft SharePoint Enterprise Server 2016
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-12
Advisory published
2026-06-09
Advisory updated
2026-06-12

Who should care

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

Technical summary

The vulnerability is caused by deserialization of untrusted data in Microsoft Office SharePoint, which allows an authorized attacker to elevate privileges over a network. The CVSS vector is CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Defensive priority

HIGH

Recommended defensive actions

  • Apply patches or updates provided by Microsoft to fix the vulnerability.
  • Restrict access to sensitive areas of the SharePoint instance.
  • Monitor for suspicious activity and implement additional security measures as needed.

Evidence notes

The vendor is identified as 'Unknown Vendor' with low confidence, and 'Microsoft' is listed as a candidate evidence with source 'reference_domain_candidate'.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45484 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45484

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

  • CVE-2026-45484 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45484

    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.