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CVE-2026-45599 Microsoft CVE debrief

CVE-2026-45599 is a HIGH severity vulnerability in Microsoft Windows. This use after free vulnerability in Universal Plug and Play (upnp.dll) allows an attacker to execute code over a network. The vulnerability was published on 2026-06-09 and modified on 2026-06-11.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 8.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-11
Advisory published
2026-06-09
Advisory updated
2026-06-11

Who should care

Administrators and users of Microsoft Windows systems, particularly those with Universal Plug and Play (UPnP) enabled, should be aware of this vulnerability.

Technical summary

The vulnerability is a use-after-free issue in the Universal Plug and Play (upnp.dll) component of Microsoft Windows. This type of vulnerability occurs when a program uses memory after it has been freed, allowing an attacker to potentially execute arbitrary code.

Defensive priority

HIGH

Recommended defensive actions

  • Apply patches from Microsoft as soon as available.
  • Disable UPnP if not required.
  • Use firewalls and network segmentation to limit exposure.
  • Monitor for suspicious network activity.

Evidence notes

The CVE-2026-45599 vulnerability has a CVSS score of 8.1 and is considered HIGH severity. The vulnerability affects multiple versions of Microsoft Windows, including Windows 10, Windows 11, and Windows Server.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45599 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45599

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

  • CVE-2026-45599 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45599

    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.