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CVE-2026-77896 Microsoft CVE debrief

CVE-2026-77896 is an integer overflow or wraparound vulnerability in the Remote Desktop Client that could allow an unauthorized attacker to deny service over a network. The vulnerability has a CVSS score of 6.5 and a severity of MEDIUM. Microsoft has released a patch for this vulnerability. System administrators and security teams should assess exposure and apply patches or mitigations to prevent potential denial of service attacks. The vulnerability affects various versions of Windows 10, Windows 11, and Windows Server. Affected systems should be reviewed for potential attacks and verified for vendor-provided patches.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-09-28
Advisory published
2026-09-08
Advisory updated
2026-09-28

Who should care

System administrators and security teams responsible for managing Remote Desktop Client systems should assess exposure and apply patches or mitigations to prevent potential denial of service attacks.

Why it matters

CVE-2026-77896 is a medium-severity vulnerability in Remote Desktop Client that could allow an unauthorized attacker to deny service. System administrators and security teams should assess exposure and apply patches or mitigations.

  • Potential denial of service attacks against Remote Desktop Client systems
  • Necessity to verify and apply vendor-provided patches
  • Need to monitor Remote Desktop Client systems for potential attacks

Technical summary

The CVE-2026-77896 vulnerability is an integer overflow or wraparound issue in the Remote Desktop Client. This could allow an unauthorized attacker to deny service over a network. The vulnerability has a CVSS score of 6.5 and a severity of MEDIUM. Affected systems include various versions of Windows 10, Windows 11, and Windows Server.

Defensive priority

Apply patches or mitigations to vulnerable Remote Desktop Client systems to prevent potential denial of service attacks.

Recommended defensive actions

  • Apply patches or mitigations to vulnerable Remote Desktop Client systems
  • Verify and apply vendor-provided patches
  • Monitor Remote Desktop Client systems for potential denial of service attacks

Evidence notes

The CVE record and NVD vulnerability detail page provide information on the vulnerability, its CVSS score, and affected systems. The vulnerability has been confirmed in various versions of Windows 10, Windows 11, and Windows Server. Microsoft has released a patch for this vulnerability. Defenders should verify and apply vendor-provided patches, and monitor Remote Desktop Client systems for potential denial of service attacks. The information provided is based on the CVE record and NVD,

Sources and references

Verified primary and authoritative sources

  • CVE-2026-77896 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-77896

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

  • CVE-2026-77896 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-77896

    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.