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CVE-2026-97840 Microsoft CVE debrief

A vulnerability in the DNS Server allows an authorized attacker to disclose information over a network due to an out-of-bounds read issue. This issue impacts DNS servers and related infrastructure, allowing attackers to access sensitive information. Defenders responsible for DNS servers, Windows infrastructure, and related security configurations should assess exposure and prioritize patching. The vulnerability is caused by an out-of-bounds read in the DNS Server, allowing an authorized attacker to disclose information over a network.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-13
Original CVE updated
2026-10-14
Advisory published
2026-10-13
Advisory updated
2026-10-14

Who should care

Defenders responsible for DNS servers, Windows infrastructure, and related security configurations should assess exposure and prioritize patching.

Why it matters

CVE-2026-97840 is a DNS Server Information Disclosure Vulnerability that allows authorized attackers to disclose information over a network. Defenders should prioritize verifying and applying patches for affected Windows versions, especially for DNS servers and related infrastructure.

  • Verify and apply patches for affected Windows versions to prevent potential information disclosure
  • Review and update DNS server configurations and access controls to limit potential attacker access
  • Monitor DNS server logs for potential exploitation attempts to detect possible attacks

Technical summary

The vulnerability is caused by an out-of-bounds read in the DNS Server, allowing an authorized attacker to disclose information over a network. This issue impacts DNS servers and related infrastructure, allowing attackers to access sensitive information. The vulnerability affects DNS servers and related infrastructure, allowing authorized attackers to disclose information over a network due to an out-of-bounds read issue.

Defensive priority

Defenders should prioritize verifying and applying patches for affected Windows versions, especially for DNS servers and related infrastructure.

Recommended defensive actions

  • Verify and apply patches for affected Windows versions
  • Review and update DNS server configurations and access controls
  • Monitor DNS server logs for potential exploitation attempts

Evidence notes

The CVE record and source item provide details on the vulnerability, affected products, and references to vendor advisories. The vulnerability affects DNS servers and related infrastructure, allowing authorized attackers to disclose information over a network due to an out-of-bounds read issue. The source item provides details on the vulnerability and affected products. Vendor advisories and patch information are available for review. The CVE Program record with source-provided CVE is

Sources and references

Verified primary and authoritative sources

  • CVE-2026-97840 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-97840

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

  • CVE-2026-97840 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-97840

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

Supplemental references

  • Role: DNS Server Information Disclosure Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/97xxx/CVE-2026-97840.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97840

    Supplemental source - vendor-advisory, patch

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.