CVE-2026-15418 in silabser.sys driver
Summary
by MITRE • 09/10/2026
In the silabser.sys driver for CP210x devices v11.5.0 and earlier, a local unprivileged user with a malicious device can use malformed packets to leak up to 145 bytes of uninitialized kernel pool memory. This vulnerability affects Windows 10 and earlier.
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Analysis
by VulDB Data Team • 09/10/2026
The vulnerability identified in the silabser.sys driver for CP210x USB-to-serial converter devices, specifically affecting versions v11.5.0 and earlier, represents a significant security risk due to its potential for information disclosure through uninitialized memory leaks. This issue is particularly concerning because it allows local unprivileged users with physical access or the ability to plug in malicious hardware to exploit kernel-level flaws without requiring elevated privileges. The core of this vulnerability lies in how the driver handles incoming data packets from connected USB devices, where a failure to properly initialize specific buffers before use leads to the exposure of sensitive kernel pool memory contents.
From a technical perspective, the flaw stems from improper initialization practices within the silabser.sys driver code. When processing malformed or specifically crafted packets sent by a malicious device acting as a CP210x emulator, the driver allocates memory for data handling but fails to zero out or properly initialize certain portions of that allocation before copying or referencing it in response messages. Consequently, when these responses are transmitted back through the USB interface, they inadvertently include residual data from previously allocated kernel pool blocks. This uninitialized memory can contain pointers, cryptographic keys, session tokens, or other sensitive information retained from prior operations by the operating system or other applications running on the host machine.
The operational impact of this vulnerability is substantial, primarily centered around unauthorized information disclosure and potential privilege escalation pathways. An attacker leveraging this flaw could extract up to 145 bytes of kernel memory per interaction, which may be sufficient to leak critical security artifacts such as stack canaries, heap metadata, or encryption keys used by other processes. This type of attack aligns with the Common Weakness Enumeration category CWE-200: Information Exposure and more specifically CWE-789: Memory Leak leading to information disclosure via uninitialized memory. In terms of tactical classification under MITRE ATT&CK, this behavior corresponds to T1056.004: Input Capture from Hardware Interfaces or potentially T1005: Data from Local System depending on the specific data extracted and its utility for further exploitation stages like credential dumping or bypassing security mechanisms such as ASLR through information leakage techniques categorized under T1074.
Mitigation strategies must focus on both immediate patching and broader hardware trust policies. The primary remediation is to update the CP210x USB-to-Serial Bridge drivers to version v11.5.1 or later, where Silicon Labs has addressed this memory initialization flaw by ensuring all allocated buffers are properly cleared before use in packet processing routines. Organizations should also implement strict device control policies using endpoint detection and response solutions that restrict unauthorized serial devices from connecting to critical systems. Additionally, enabling hardware-based security features such as USB port blocking for non-whitelisted vendors can prevent attackers from introducing malicious emulated CP210x devices into the environment. Regular auditing of connected peripheral devices and monitoring for anomalous kernel memory access patterns can further enhance detection capabilities against this specific class of vulnerabilities.