PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-78457 Microsoft CVE debrief

CVE-2026-78457 is a high-severity vulnerability in Windows Security Health Service that allows an authorized attacker to elevate privileges locally. The CVE record was published on 2026-09-08T18:20:44.407Z and was last modified on 2026-09-11T18:54:07.420Z. The NVD entry is currently Analyzed. This vulnerability is a use-after-free issue affecting Windows 11 24H2, 25H2, 26H1, Windows Server 2022, and Windows Server 2025. Defenders should prioritize patching, verify affected versions, and monitor system logs for potential exploitation attempts. Microsoft has provided patches for this vulnerability, and it is essential to apply them or workarounds as recommended.

Vendor
Microsoft
Product
Windows 11 Version 24H2
CVSS
HIGH 7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-08
Original CVE updated
2026-10-14
Advisory published
2026-09-08
Advisory updated
2026-10-14

Who should care

Defenders responsible for Windows systems, especially those with high-risk exposure, should prioritize patching this vulnerability. Verify affected Windows versions and apply patches or workarounds as recommended by Microsoft.

Why it matters

CVE-2026-78457 is a high-severity vulnerability in Windows Security Health Service that allows an authorized attacker to elevate privileges locally. Defenders should prioritize patching, verify affected versions, and monitor system logs.

  • Potential local privilege escalation requires verification from official sources.
  • Defenders should verify affected Windows versions and apply patches or workarounds.
  • Monitoring system logs for potential exploitation attempts is recommended.

Technical summary

CVE-2026-78457 is a high-severity vulnerability in Windows Security Health Service that allows an authorized attacker to elevate privileges locally. The vulnerability is described as a use-after-free issue. Affected versions include Windows 11 24H2, 25H2, 26H1, Windows Server 2022, and Windows Server 2025. Microsoft has provided patches for this vulnerability.

Defensive priority

Defenders should prioritize patching this vulnerability, especially for systems with high-risk exposure. Verify affected Windows versions and apply patches or workarounds as recommended by Microsoft.

Recommended defensive actions

  • Apply patches or workarounds as recommended by Microsoft for affected Windows versions.
  • Verify affected Windows versions and prioritize patching for systems with high-risk exposure.
  • Monitor system logs for potential exploitation attempts.

Evidence notes

The vulnerability is described as a use-after-free issue in Windows Security Health Service. Microsoft has provided a patch for this vulnerability. Affected versions include Windows 11 24H2, 25H2, 26H1, Windows Server 2022, and Windows Server 2025.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-78457 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-78457

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

  • CVE-2026-78457 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-78457

    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.