CVE-2026-15419

A buffer overflow classified as CWE-121 in silabser.sys, the Windows kernel driver for Silicon Labs CP210x USB-to-UART bridge devices, version 11.5.0 and earlier, allows kernel pool memory to be corrupted via malformed packets sent by the device. An unprivileged local user who connects — or already controls — a malicious USB device that enumerates as a CP210x device can trigger the corruption, yielding arbitrary code execution with escalated (kernel-level) privileges on the host. CVSS 4.0 rates the attack vector as physical with no privileges required and High impact on confidentiality, integrity, and availability. Any Windows machine with the Silicon Labs CP210x driver (v11.5.0 or earlier) installed is affected, with practical risk limited to hosts where an untrusted user or device can reach a USB port. No exploitation in the wild, public proof-of-concept, or CISA KEV listing is currently known.

What to do: Upgrade silabser.sys on all Windows hosts that use CP210x devices to the first fixed release newer than v11.5.0, checking Silicon Labs' security advisory for the exact patched build. Until patched, restrict which USB devices can be connected to sensitive hosts, since exploitation requires physical access with a malicious device that enumerates as a CP210x. Verify the installed driver version via Device Manager or the version properties of the silabser.sys file.