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CVE-2026-49800 Microsoft CVE debrief

CVE-2026-49800 is an integer overflow or wraparound vulnerability in the Windows Web Proxy Auto-Discovery Protocol (WPAD). An authorized attacker can exploit this vulnerability locally to elevate privileges. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. This type of vulnerability can be particularly dangerous as it allows an attacker with local access to gain elevated privileges, potentially leading to further exploitation. System administrators should be aware of this vulnerability and take steps to mitigate it.

Vendor
Microsoft
Product
Windows 10 Version 1809
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-22
Advisory published
2026-07-14
Advisory updated
2026-07-22

Who should care

System administrators and users of Microsoft Windows operating systems should be aware of this vulnerability, as it can be exploited locally by an authorized attacker to elevate privileges. This vulnerability is particularly concerning for organizations that have users with local access to Windows systems, as it could be used as a stepping stone for further attacks.

Technical summary

The vulnerability exists in the Windows Web Proxy Auto-Discovery Protocol (WPAD) due to an integer overflow or wraparound. This can be exploited by an authorized attacker to elevate privileges locally. The vulnerability affects various versions of Microsoft Windows, including Windows 10, Windows 11, and Windows Server. The attack vector is local, and the vulnerability does not require any special conditions to be exploited.

Defensive priority

High

Recommended defensive actions

  • Apply patches provided by Microsoft
  • Ensure that Windows operating systems are up-to-date
  • Monitor system logs for suspicious activity
  • Implement additional security measures, such as access controls and intrusion detection systems
  • Review compensating controls for exposed systems while remediation is scheduled and verified

Evidence notes

The CVE record was published on 2026-07-14T17:16:56.193Z and was last modified on 2026-07-16T15:40:16.100Z. The NVD entry is currently Analyzed. The vulnerability affects various versions of Microsoft Windows, including Windows 10, Windows 11, and Windows Server. However, specific details about the impact on each version are limited. Defenders should verify the affected scope and review system logs for potential exploitation attempts.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-49800 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-49800

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

  • CVE-2026-49800 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-49800

    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.