Hi, The patch in this bug report very much shrinks the window of the vulnerability, but doesn't close it completely: the file is still created with default permissions, then chmodded as a separate step. It's hard, but not impossible to still win the race and open the file before the chmod, enabling the same attack. I recommend something like
fd = open(dstFileName, O_WRONLY|O_CREAT|O_EXCL, 0600); if (fd != -1) f = fdopen( fd, "wb" ); if (fd == -1 || f == NULL) DISPLAYLEVEL(1, "zstd: %s: %s\n", dstFileName, strerror(errno)); return f; for example. -- Regards, Feri