Double-free vulnerability in the FTP-kerberos code in cURL 7.52.0 to 7.65.3.

cURL libcurl is vulnerable to a heap-based buffer overflow, caused by improper bounds checking by the tftpreceivepacket function. By sending specially-crafted request containing an OACK without the BLKSIZE option, a remote attacker could overflow a buffer and execute arbitrary code on the system.

A non-privileged user or program can put code and a config file in a known non-privileged path (under C:/usr/local/) that will make curl <= 7.65.1 automatically run the code (as an openssl "engine") on invocation. If that curl is invoked by a privileged user it can do anything it wants.

A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versions 7.19.4 through 7.64.1.