TinyUSB through 0.21.0, fixed in commit e85c2b8, contains an out-of-bounds write vulnerability in the MTP device class helper mtp_container_get_string() in src/class/mtp/mtp.h that allows a malicious USB host to corrupt adjacent memory by supplying a crafted MTP string with an unbounded character count. Attackers can exploit the unchecked memcpy operation copying up to 510 bytes into a fixed-size destination buffer to achieve code execution or cause a denial of service on the TinyUSB MTP device.