The NEEDBITS macro in the inflate_dynamic function in inflate.c for unzip can be invoked using invalid buffers, which allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via unknown vectors that trigger a free of uninitialized or previously-freed data.

Buffer overflow in UnZip 5.50 and earlier allows user-assisted attackers to execute arbitrary code via a long filename command line argument. NOTE: since the overflow occurs in a non-setuid program, there are not many scenarios under which it poses a vulnerability, unless unzip is passed long arguments when it is invoked from other programs.

Unzip 5.51 and earlier does not properly warn the user when extracting setuid or setgid files, which may allow local users to gain privileges.

Directory traversal vulnerability in UnZip 5.50 allows attackers to overwrite arbitrary files via invalid characters between two . (dot) characters, which are filtered and result in a ".." sequence.