Intelligence online17 sources monitored8 actively exploited 7d26 published 24hChecked recently
Vulnerability record

CVE-2026-85880

Microsoft Windows Heap-Based Buffer Overflow Vulnerability

HighExploitation confirmedCISA KEV
What should I do?

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Windows, fix it now.

CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

US federal civilian agencies must remediate by Sep 22, 2026.

Patch status

Official fix available since

Apply the vendor's update to every affected system. Check the fixed-in versions below where known.

Basis: NVD patch reference

Description

Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.

Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.

Affected products

ProductVendorSource
WindowsMicrosoftKEV

Sources: KEV = CISA Known Exploited Vulnerabilities catalog. Version details have not been published yet.

Intelligence timeline

Developments from the last 30 days, newest first.

  1. CVSS scoredUpdateKEV

    CVE-2026-85880 scored CVSS 7.8: Microsoft Windows, Microsoft Windows Heap-Based Buffer Overflow Vulnerability

    CISA lists this as exploited in the wild. Unpatched Windows systems are exposed to active attacks now.

    Basis: NIST National Vulnerability Database

  2. Patch releasedUpdateKEV

    Patch released for CVE-2026-85880: Microsoft Windows, Microsoft Windows Heap-Based Buffer Overflow Vulnerability

    An official fix is now available for Microsoft Windows. This vulnerability is being exploited, so apply it promptly.

    Basis: NVD patch reference

  3. Added to CISA KEV

    CVE-2026-85880 added to CISA KEV: Microsoft Windows, Microsoft Windows Heap-Based Buffer Overflow Vulnerability

    CISA lists this as exploited in the wild. Unpatched Windows systems are exposed to active attacks now.

    Basis: CISA Known Exploited Vulnerabilities catalog

Coverage

We have not published a story about this vulnerability yet.

References

  • msrc.microsoft.com https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-85880
  • cisa.gov https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
  • cisa.gov https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-ba…
  • nvd.nist.gov https://nvd.nist.gov/vuln/detail/CVE-2026-85880
  • msrc.microsoft.com https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85880
  • cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880