CVE-2025-32706
Microsoft Windows Common Log File System (CLFS) Driver Heap-Based Buffer Overflow Vulnerability
Description
CVE-2025-32706 is a high-severity improper input validation vulnerability in the Microsoft Windows Common Log File System (CLFS) Driver that enables local privilege escalation. The flaw allows an authorized attacker with low-level privileges to escalate to SYSTEM-level access by exploiting insufficient validation of data processed by the CLFS driver. With a CVSS v3.1 base score of 7.8, this vulnerability poses a serious threat to virtually all supported Windows client and server editions. CISA has added CVE-2025-32706 to the Known Exploited Vulnerabilities catalog with a remediation deadline of June 3, 2025, and its EPSS score of 1.3% at the 79th percentile reflects meaningful exploitation probability, particularly given confirmed active exploitation in the wild.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | windows 10 1507 | < 10.0.10240.21014 |
| microsoft | windows 10 1607 | < 10.0.14393.8066 |
| microsoft | windows 10 1809 | < 10.0.17763.7314 |
| microsoft | windows 10 21h2 | < 10.0.19044.5854 |
| microsoft | windows 10 22h2 | < 10.0.19045.5854 |
| microsoft | windows 11 22h2 | < 10.0.22621.5335 |
| microsoft | windows 11 23h2 | < 10.0.22631.5335 |
| microsoft | windows 11 24h2 | < 10.0.26100.3981 |
| microsoft | windows server 2008 | -; r2 |
| microsoft | windows server 2012 | r2 |
| microsoft | windows server 2016 | < 10.0.14393.8066 |
| microsoft | windows server 2019 | < 10.0.17763.7314 |
| microsoft | windows server 2022 | < 10.0.20348.3692 |
| microsoft | windows server 2022 23h2 | < 10.0.25398.1611 |
| microsoft | windows server 2025 | < 10.0.26100.3981 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-32706(Vendor Advisory)
- https://www.vicarius.io/vsociety/posts/cve-2025-32706-detection-script-elevation-of-privilege-vulnerability-in-microsoft-windows-common-log-file-system-driver(Exploit, Third Party Advisory)
- https://www.vicarius.io/vsociety/posts/cve-2025-32706-mitigation-script-elevation-of-privilege-vulnerability-in-microsoft-windows-common-log-file-system-driver(Exploit, Mitigation, Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-32706(US Government Resource)
Weakness Type
CWE-20: Improper Input Validation
CVE-2025-32706 is classified under CWE-20, Improper Input Validation. This weakness occurs when software receives input that it does not validate or incorrectly validates, allowing an attacker to craft input in a form that is not expected by the application. In the Windows CLFS driver, certain input data is not adequately validated before being processed at the kernel level, enabling a local attacker to manipulate driver operations and escalate privileges from a standard user context to SYSTEM.
Learn more: CWE-20 — Improper Input Validation
Impact Analysis
CVE-2025-32706 carries a CVSS v3.1 score of 7.8 (High), reflecting its significant local impact. The vulnerability requires local access (AV:L) with low attack complexity (AC:L), meaning an attacker who has already gained a foothold on the system, even with limited privileges (PR:L), can exploit it without any user interaction (UI:N). Successful exploitation results in complete compromise of confidentiality, integrity, and availability on the affected system, as the attacker gains SYSTEM-level privileges. This means full read and write access to all files, the ability to install persistent backdoors, create new administrator accounts, disable security tools, and manipulate audit logs. The Windows CLFS driver is a core kernel component present across all modern Windows versions, making the attack surface extremely broad, spanning Windows 10, Windows 11, and Windows Server editions from 2008 through 2025. With an EPSS score at the 79th percentile and confirmed active exploitation, this vulnerability represents a critical post-compromise escalation vector.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2025-32706 in the wild by adding it to the Known Exploited Vulnerabilities catalog on May 13, 2025, with a remediation deadline of June 3, 2025. Public exploit resources are available via Vicarius vSociety detection and mitigation scripts, providing both detection and mitigation guidance. The EPSS score of 1.3% at the 79th percentile indicates above-average exploitation probability. The CLFS driver has been a recurring target for privilege escalation exploits, with multiple CLFS vulnerabilities exploited in the wild in recent years, making this a well-understood attack surface for threat actors seeking to elevate local access to full system control.
Remediation
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Apply the May 2025 Patch Tuesday security updates immediately. Microsoft has released patches for all affected Windows versions. Consult the Microsoft Security Response Center advisory for version-specific KB articles and download links. CISA requires federal agencies to remediate by June 3, 2025.
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Prioritize patching across all Windows editions, including Windows 10 (all supported versions below 10.0.10240.21014 through 10.0.19045.5854), Windows 11 (below 10.0.22621.5335, 10.0.22631.5335, and 10.0.26100.3981), and all Windows Server versions from 2008 through 2025.
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Implement least-privilege access controls to limit the number of users with local logon access to critical systems. Since this vulnerability requires local access with low privileges, reducing the local attack surface is an effective interim mitigation.
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Monitor for signs of exploitation by reviewing Windows Event Logs for anomalous CLFS driver activity, unexpected SYSTEM-level process creation, and privilege escalation indicators. Deploy endpoint detection and response (EDR) rules targeting CLFS exploitation patterns.
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Harden systems against post-exploitation by enabling Credential Guard, restricting administrative tool access, and implementing application control policies to prevent unauthorized code execution even if privilege escalation succeeds.
Technical Details
CVE-2025-32706 is a local privilege escalation vulnerability in the Windows Common Log File System (CLFS) driver caused by improper input validation (CWE-20). The CVSS v3.1 vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H confirms this is a locally exploitable flaw requiring low privileges and no user interaction, with high impact across confidentiality, integrity, and availability. The CLFS driver is a kernel-mode component that manages transactional logging for the Windows operating system; it processes Base Log File (BLF) structures that contain metadata blocks and container records. The vulnerability arises from insufficient validation of crafted input processed by the driver, allowing an attacker to corrupt internal driver state or trigger memory operations that lead to code execution in kernel context. Once kernel-level execution is achieved, the attacker operates with SYSTEM privileges, effectively bypassing all user-mode security boundaries. This vulnerability affects every supported Windows version, from Windows 10 1507 and Windows Server 2008 through the latest Windows 11 24H2 and Windows Server 2025 releases.
Frequently Asked Questions
Is CVE-2025-32706 being actively exploited?
Yes. CISA has confirmed active exploitation of CVE-2025-32706 by adding it to the Known Exploited Vulnerabilities catalog on May 13, 2025. Public detection and mitigation scripts are also available through Vicarius, indicating the exploit is well-understood by the security community.
What products are affected by CVE-2025-32706?
CVE-2025-32706 affects virtually all supported Microsoft Windows editions, including Windows 10 (versions 1507 through 22H2), Windows 11 (22H2, 23H2, and 24H2), and Windows Server 2008, 2008 R2, 2012, 2012 R2, 2016, 2019, 2022, 2022 23H2, and 2025. Each platform has specific patched build numbers.
How do I fix CVE-2025-32706?
Apply the May 2025 security updates from Microsoft for all affected Windows systems. Check the Microsoft Security Response Center advisory for the specific KB article corresponding to your Windows version. As interim mitigations, restrict local logon access and monitor for CLFS-related exploitation activity.
How severe is CVE-2025-32706?
CVE-2025-32706 has a CVSS v3.1 score of 7.8 (High), reflecting complete compromise of the affected system's confidentiality, integrity, and availability upon successful exploitation. Its EPSS score at the 79th percentile and confirmed active exploitation place it among the more urgently actionable Windows privilege escalation vulnerabilities.
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