CVE-2025-24983: Microsoft Windows Win32k Use-After-Free Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Microsoft Windows. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-03-11, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-04-01; treat that as the outer limit, not the target.
• EPSS 1.4%, percentile 72: FIRST’s model estimates a 1.4% chance of exploitation activity in the next 30 days, higher than 72% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.

What it is

Use after free in Windows Win32 Kernel Subsystem allows an authorized attacker to elevate privileges locally.

CISA’s summary

Microsoft Windows Win32 Kernel Subsystem contains a use-after-free vulnerability that allows an authorized attacker to elevate privileges locally.

Weakness type: CWE-416.

Product: Microsoft Windows · Assigned by: microsoft · Published: 2025-03-11

Affected and fixed versions

Severity scores

• Attack vector: local access needed
• Attack complexity: high (needs special conditions)
• Privileges required: low (any account)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2025-03-11; federal due date 2025-04-01. Known ransomware use: Unknown.
• CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
• CISA SSVC assessment: exploitation active, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 1.38% probability of exploitation activity in the next 30 days; percentile 72.

Timeline

• 2025-03-11 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2025-03-11 — CVE record published by microsoft
• 2025-04-01 — CISA remediation deadline for US federal agencies
• 2026-02-26 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. Windows Win32 Kernel Subsystem Elevation of Privilege Vulnerability msrc.microsoft.com
2. Listed in CISA KEV notes (msrc.microsoft.com) msrc.microsoft.com

Vulnerability records

1. CVE.org record CVE-2025-24983 cve.org
2. NVD entry CVE-2025-24983 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

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