What is the CVSS score of CVE-2023-36424?

CVE-2023-36424 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 10.3%.

Which versions of Windows CLFS Driver are affected by CVE-2023-36424?

A local privilege escalation vulnerability in the Windows CLFS driver enables authenticated low-privileged users to escalate to SYSTEM level, granting complete system control.. A patch is available.

Is there a public PoC exploit available for CVE-2023-36424?

Yes, a public proof-of-concept exploit is available for CVE-2023-36424. Prioritise patching immediately. EPSS: 10.3%.

How to fix or mitigate CVE-2023-36424?

Within 24 hours: Identify and catalog all Windows 10 (versions 1507 through 22H2) and Windows 11 21H2 systems in your environment. Within 7 days: Deploy Microsoft's monthly Patch Tuesday security updates containing CVE-2023-36424 fixes to all affected systems via WSUS or equivalent patch management tool. Within 30 days: Verify 100% patch compliance across the environment and implement detection rules in your EDR/SIEM platforms for exploitation attempts targeting the CLFS driver.

Windows CLFS Driver CVE-2023-36424

HIGH

Out-of-bounds Read (CWE-125)

2023-11-14 secure@microsoft.com

Buffer Overflow Microsoft Information Disclosure

7.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.8 HIGH

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Added to CISA KEV

Apr 13, 2026 - 18:57 CISA

DescriptionCVE.org

Windows Common Log File System Driver Elevation of Privilege Vulnerability

AnalysisAI

Local privilege escalation in the Windows Common Log File System (CLFS) driver allows authenticated low-privileged attackers to elevate to SYSTEM on Windows 10 (1507 through 22H2) and Windows 11 21H2. The flaw is confirmed actively exploited (CISA KEV) with publicly available exploit code, and EPSS places it in the 93rd percentile for exploitation likelihood. Microsoft has released patches via standard monthly updates.

Technical ContextAI

The Common Log File System (clfs.sys) is a kernel-mode driver shipped with Windows that provides a general-purpose transactional logging facility used by services, the kernel transaction manager, and applications. The CWE-125 (out-of-bounds read) classification, combined with the 'Buffer Overflow' tag, indicates the driver reads past the bounds of an allocated buffer when parsing attacker-supplied CLFS log file structures (.BLF files or related log containers), which has historically been a fruitful target for kernel EoP because CLFS log parsing is reachable from user mode and runs in ring 0. The CPE list confirms every supported Windows 10 servicing branch (1507/1607/1809/21H2/22H2) on x86, x64, and ARM64, plus Windows 11 21H2 are affected, indicating a long-standing defect in the shared CLFS code path.

RemediationAI

Apply the Microsoft security update for CVE-2023-36424 from the November 2023 Patch Tuesday cycle (vendor-released patch available) by installing the appropriate cumulative update for each affected Windows 10 servicing branch (1507/1607/1809/21H2/22H2) and Windows 11 21H2, consulting Microsoft's MSRC advisory for the exact KB number per build. Because the vulnerability is in clfs.sys and reachable from any local user, there is no clean configuration workaround; compensating controls until patching is complete include enforcing least-privilege so that initial-access malware lands as a constrained user (to slow but not prevent the EoP), enabling Microsoft Defender / EDR rules targeting known public CLFS exploit primitives, and using attack surface reduction rules and application allowlisting to limit which binaries can run and thereby invoke the vulnerable driver - none of these block the bug itself, only narrow the population of attackers who can reach it.