CVE 2007-4135
The NFSv4 ID mapper (nfsidmap) before 0.17 does not properly handle return values from the getpwnam_r function when performing a username lookup, which can cause it to report a file as being owned by "root" instead of "nobody" if the file exists on the server but not on the client.
See the 
CVE page on Mitre.org
for more details.
