CVE-2026-109836 in Core Temp
Summary
by MITRE • 11/04/2026
The Core Temp kernel driver provided by ALCPU is vulnerable to insufficient access control in an exposed IOCTL, which may allow physical memory to be read or written.
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Analysis
by VulDB Data Team • 11/04/2026
The vulnerability identified within the Core Temp kernel driver developed by ALCPU represents a critical failure in operating system security boundaries due to insufficient access control mechanisms on an input/output control (IOCTL) interface. Kernel drivers operate with ring 0 privileges, granting them unrestricted access to hardware and physical memory resources. When such drivers expose IOCTL endpoints without rigorous validation of the caller's identity or privilege level, they create a direct pathway for malicious actors to interact directly with sensitive kernel structures. This specific flaw allows any process running on the system, regardless of its user context, to issue commands that bypass standard security checks, effectively treating privileged operations as if they were performed by an administrator or even the operating system itself.
From a technical perspective, this vulnerability falls under CWE-284 Improper Access Control and is closely related to CWE-770 Allocation of Resources Without Limits or Throttling when it involves resource exhaustion, but primarily manifests here as unauthorized memory access. The core issue lies in the driver's failure to verify that the requesting process possesses the necessary security tokens or privileges before executing sensitive operations. In Windows environments, IOCTLs are typically gated by device object security descriptors which define who can open and communicate with a driver. If these descriptors are misconfigured or if the internal logic of the IOCTL handler does not perform additional checks on the caller's integrity level, an attacker can exploit this gap to read from or write to arbitrary physical memory addresses. This capability is particularly dangerous because it circumvents user-mode protections such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR), which are designed to prevent exploitation of vulnerabilities in applications running at lower privilege levels.
The operational impact of this vulnerability is severe, enabling a wide range of malicious activities that compromise the confidentiality, integrity, and availability of the affected system. An attacker with local access can leverage this flaw to dump kernel memory contents, potentially extracting cryptographic keys, session tokens, or credentials stored in plaintext within kernel structures. Furthermore, the ability to write to physical memory allows for privilege escalation attacks where an unprivileged user can modify kernel data structures to elevate their own process privileges to SYSTEM level. This effectively grants full control over the operating system, allowing the installation of rootkits, persistence mechanisms, and further lateral movement across a network. The vulnerability aligns with MITRE ATT&CK technique T1055 Process Injection and specifically T1069 Permission Groups Discovery when used for reconnaissance, but most critically it facilitates T1055.013 Internal OS Credential Dumping and T1068 Exploitation for Privilege Escalation by allowing direct manipulation of kernel memory spaces that are normally inaccessible to user-mode applications.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary solution is to apply the vendor-provided patch or update that addresses the access control logic within the Core Temp driver, ensuring that IOCTL handlers properly validate caller privileges before executing sensitive operations. Administrators should also consider disabling or removing the driver if it is not actively required for system functionality, thereby reducing the attack surface entirely. For environments where the driver must remain installed, implementing strict application whitelisting policies can prevent unauthorized processes from attempting to open handles to the device object associated with the driver. Additionally, enabling advanced kernel protection features such as Kernel Patch Protection (PatchGuard) and Memory Integrity in Windows Defender System Guard provides an additional layer of defense by detecting and blocking unauthorized modifications to critical kernel code and data structures, although these measures may not prevent all forms of memory reading depending on specific implementation details. Regular auditing of driver installations and monitoring for unusual IOCTL activity through endpoint detection and response (EDR) solutions can also aid in early detection of exploitation attempts targeting this vulnerability.