CVE-2025-24983
Microsoft Windows Win32k Use-After-Free Vulnerability
Description
CVE-2025-24983 is a high-severity use-after-free vulnerability in the Windows Win32 Kernel Subsystem that allows a locally authenticated attacker to elevate privileges to SYSTEM level. The vulnerability exists in kernel memory management where a freed object can be referenced after deallocation, enabling an attacker to execute arbitrary code with elevated privileges. With a CVSS v3.1 score of 7 and HIGH severity, the vulnerability requires local access and low privileges but has high attack complexity. CISA has confirmed active exploitation by adding CVE-2025-24983 to the KEV catalog with a remediation deadline of 2025-04-01, and its EPSS score of 0.67% at the 71.0th percentile reflects meaningful exploitation in targeted attacks.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | windows 10 1507 | < 10.0.10240.20947 |
| microsoft | windows 10 1607 | < 10.0.14393.7876 |
| microsoft | windows server 2008 | -; r2 |
| microsoft | windows server 2012 | -; r2 |
| microsoft | windows server 2016 | < 10.0.14393.7876 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-24983(Patch, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-24983(US Government Resource)
Weakness Type
CWE-416: Use After Free
CVE-2025-24983 is classified under CWE-416 (Use After Free), which occurs when a program continues to reference memory after it has been freed, potentially leading to corruption of valid data or code execution. In the Windows Win32 Kernel Subsystem, a race condition allows a freed kernel object to be accessed, enabling an attacker to manipulate the freed memory to achieve privilege escalation.
Learn more: CWE-416 — Use After Free
Impact Analysis
The impact of CVE-2025-24983 spans all three CIA triad dimensions with high severity. The vulnerability requires local access (AV:L), has high attack complexity (AC:H), and needs low privileges (PR:L) with no user interaction (UI:N). Confidentiality (High): Successful privilege escalation to SYSTEM allows reading any file or registry entry on the machine, including credentials, tokens, and sensitive configuration data. Integrity (High): SYSTEM-level access enables modification of any file, installation of persistent backdoors, and manipulation of security policies. Availability (High): An attacker at SYSTEM level can disable services, corrupt system files, or render the machine inoperable. With a CVSS score of 7 (HIGH) and an EPSS score of 0.67% at the 71.0th percentile, the high attack complexity somewhat limits widespread exploitation, but the vulnerability has been confirmed as actively exploited in targeted attacks against legacy Windows systems.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2025-24983 by adding it to the Known Exploited Vulnerabilities catalog, confirming that the Windows Win32 Kernel Subsystem use-after-free is being leveraged in real-world privilege escalation attacks. The EPSS score of 0.67% at the 71.0th percentile reflects targeted exploitation rather than widespread campaigns, consistent with the high attack complexity (AC:H) requirement. The ransomware association is classified as unknown. No public proof-of-concept exploit has been identified in the available references, but the confirmed active exploitation indicates that sophisticated threat actors have developed reliable exploits. The vulnerability primarily affects legacy Windows versions (Windows 10 1507/1607 and Windows Server 2008/2012/2016), suggesting it is being used in targeted attacks against organizations still running older Windows infrastructure.
Remediation
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Apply the March 2025 security update from Microsoft. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. The patch addresses the use-after-free condition in the Win32 Kernel Subsystem and is available via Windows Update, WSUS, or the Microsoft Update Catalog.
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Prioritize patching legacy systems running Windows 10 1507, Windows 10 1607, Windows Server 2008, Windows Server 2012, and Windows Server 2016, as these are the confirmed affected platforms. Develop an accelerated patching schedule for these older systems.
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Implement kernel exploit mitigations including Credential Guard, Hypervisor-Protected Code Integrity (HVCI), and exploit protection policies. These defense-in-depth measures can make kernel exploitation significantly more difficult even before patches are applied.
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Monitor for privilege escalation indicators including unexpected SYSTEM-level process creation, suspicious kernel crash dumps, and anomalous behavior from low-privileged user accounts. Deploy EDR rules targeting use-after-free exploitation patterns in the Win32 subsystem.
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Plan migration from legacy Windows versions where this vulnerability is confirmed. Windows Server 2008 and 2012 are no longer receiving mainstream support, and their continued use represents an ongoing security risk beyond this specific CVE.
Technical Details
CVE-2025-24983 is a use-after-free vulnerability (CWE-416) in the Windows Win32 Kernel Subsystem with the CVSS v3.1 vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. The vulnerability exists in the kernel's handling of Win32k objects, where a race condition allows a thread to free a kernel object while another thread still holds a reference to it. When the second thread subsequently accesses the freed memory, it may read corrupted data or execute attacker-controlled code placed in the freed memory region through heap manipulation techniques. The high attack complexity (AC:H) reflects the race condition timing requirement, which makes exploitation non-trivial but achievable with careful synchronization. The local vector (AV:L) with low privileges (PR:L) confirms this is a local privilege escalation vulnerability where an authenticated user can elevate to SYSTEM. The scope is unchanged (S:U), meaning the elevated privileges remain within the Windows kernel security boundary. The vulnerability specifically affects older Windows versions (Windows 10 1507/1607 and Server 2008/2012/2016), suggesting the vulnerable code path was refactored or replaced in newer Windows builds.
Frequently Asked Questions
Is CVE-2025-24983 being actively exploited?
Yes, CISA has confirmed active exploitation by adding CVE-2025-24983 to the KEV catalog. The exploitation is targeted rather than widespread, consistent with the high attack complexity requirement. The ransomware association is currently unknown.
What products are affected by CVE-2025-24983?
CVE-2025-24983 primarily affects older Windows versions: Windows 10 1507, Windows 10 1607, Windows Server 2008 (including R2), Windows Server 2012 (including R2), and Windows Server 2016. Newer Windows versions are not listed as affected.
How do I fix CVE-2025-24983?
Apply the March 2025 Microsoft security update through Windows Update or WSUS. Prioritize legacy systems that are specifically affected. Enable kernel exploit mitigations including Credential Guard and HVCI where supported.
How severe is CVE-2025-24983?
CVE-2025-24983 has a CVSS score of 7 (HIGH) and enables local privilege escalation to SYSTEM through a use-after-free in the kernel. While the high attack complexity limits widespread exploitation, confirmed active exploitation makes remediation urgent for affected legacy systems.
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