zip is a compression and file packaging utility.
zip does not check the resulting path length when doing recursive folder compression.
An attacker could exploit this by enticing another user or web application to create an archive including a specially-crafted path name, potentially resulting in the execution of arbitrary code with the permissions of the user running zip.
There is no known workaround at this time.
All zip users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-arch/zip-2.3-r4"