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CVE-2026-66301 Microsoft CVE debrief

Microsoft Dynamics 365 (On-Premises) Information Disclosure Vulnerability allows an authorized attacker to disclose information over a network. The vulnerability has a CVSS score of 6.5 and a severity of MEDIUM. The CVE record was published on 2026-08-11T17:05:19.979Z and last modified on 2026-10-08T18:11:39.205Z. This vulnerability affects Microsoft Dynamics 365 (on-premises) version 9.1, allowing information disclosure. Defenders should verify exposure, assess risks, and prioritize patching to prevent potential information disclosure.

Vendor
Microsoft
Product
Microsoft Dynamics 365 (on-premises) version 9.1
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-11
Original CVE updated
2026-10-08
Advisory published
2026-08-11
Advisory updated
2026-10-08

Who should care

Defenders responsible for Microsoft Dynamics 365 (on-premises) deployments, particularly those using version 9.1, should assess exposure and prioritize patching.

Why it matters

CVE-2026-66301 is a MEDIUM-severity vulnerability in Microsoft Dynamics 365 (on-premises) that allows information disclosure. Defenders should verify exposure, assess risks, and prioritize patching to prevent potential information disclosure.

  • Verify exposure of Microsoft Dynamics 365 (on-premises) version 9.1 to this vulnerability
  • Assess potential information disclosure risks
  • Prioritize patching if vulnerable
  • Monitor for potential information disclosure

Technical summary

The vulnerability allows an authorized attacker to disclose information over a network in Microsoft Dynamics 365 (on-premises) version 9.1. This information disclosure vulnerability has a CVSS score of 6.5 and a severity of MEDIUM. The vulnerability affects Microsoft Dynamics 365 (on-premises) deployments, particularly those using version 9.1. Defenders should prioritize verifying exposure and apply patches if available.

Defensive priority

Defenders should prioritize verifying exposure of Microsoft Dynamics 365 (on-premises) version 9.1 to this vulnerability and apply patches if available.

Recommended defensive actions

  • Verify exposure of Microsoft Dynamics 365 (on-premises) version 9.1 to this vulnerability
  • Apply patches if available
  • 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. The source item and CVE Program record provide some information, but there is limited evidence on the potential impact or exploitation of this vulnerability. Defenders should verify the exposure of Microsoft Dynamics 365 (on-premises) version 9.1 to this vulnerability and assess potential information disclosure risks.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-66301 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-66301

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

  • CVE-2026-66301 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-66301

    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.