ClosedPatched

Microsoft Windows: Windows Win32k Improper Resource Shutdown or Release Vulnerability

Microsoft Windows

Microsoft Windows Win32k contains an improper resource shutdown or release vulnerability that allows for local, authenticated privilege escalation. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. Added to CISA KEV on 2025-03-03.

Why this severity: CVSS 8.4 (CISA ADP, v3.1); actively exploited (CISA KEV); known ransomware use

Started: Mar 3, 2025
Closed: Mar 3, 2025
CVE: CVE-2018-8639

Follow this incident

Updated Mar 3, 2025

Affected

See vendor advisory / CISA notes (versions not always listed in KEV feed)

Fixed in

See vendor advisory linked in sources

Timeline1

Mar 3, 2025
CISA added CVE-2018-8639 to the KEV catalog (due 2025-03-24).

Advisories3

Notes & caveats

Derived from CISA KEV JSON feed catalogVersion 2026.10.21. CVSS from the CVE record (cvelistV5). Exact affected/fixed version strings are not always in the KEV record; verify against the vendor advisory URL. startedAt uses dateAdded (exploitation may have begun earlier; many entries are older CVEs newly confirmed as exploited in 2025).

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