Signedness error in ccid_serial.c in libccid in the USB Chip/Smart Card Interface Devices (CCID) driver, as used in pcscd in PCSC-Lite 1.5.3 and possibly other products, allows physically proximate attackers to execute arbitrary code via a smart card with a crafted serial number that causes a negative value to be used in a memcpy operation, which triggers a buffer overflow.  NOTE: some sources refer to this issue as an integer overflow.