lrzsz before 0.13.0 contains an OS command injection vulnerability in the lrz receive utility's pipe mode that allows remote senders to execute commands by supplying crafted filenames. When lrz runs under a suffixed name such as lrztar, procheader() in src/lrz.c passes the unescaped ZMODEM/YMODEM filename to popen(), so shell metacharacters execute as the receiving user.

lrzsz before 0.13.0 contains a path traversal vulnerability in the lrz receive utility's restricted mode that allows malicious ZMODEM senders to write files outside the current directory using absolute pathnames. Because checkpath() in src/lrz.c only rejects '../' sequences unless built with --enable-pubdir, attackers can send files named with absolute paths to overwrite any file writable by the receiving user.

lrzsz before 0.13.0 contains a heap-based buffer overflow vulnerability in procheader() of the lrz receive utility when copying overlong sender-supplied filenames into Pathname. Malicious ZMODEM senders can supply filenames up to 8192 bytes, overflowing the buffer via sprintf() in pipe mode or strcpy() to corrupt heap memory and crash lrz.

Lrzsz has an integer overflow vulernability in the src/zm.c:zsdata() function. An attacker could exploit this with the sz command to cause a crash or potentially leak information to the receiving server.

Additional References:

https://bugzilla.novell.com/showbug.cgi?id=1090051