Multiple buffer overflows in the POSIX readdir_r function as used in multiple packages allow local users to cause a denial of service and possibly execute arbitrary code via (1) a symlink attack that exploits a race condition between opendir and pathcon calls and changes the filesystem to one with a larger maximum directory-entry name length or (2) possibly via programmer-introduced errors on operating systems with a small struct dirent such as Solaris or BeOS as demonstrated in packages including (a) gcj (b) KDE (c) libwww (d) the Rudiments library (e) teTeX (f) xmail (g) bfbtester (h) ncftp (i) netwib (j) OpenOffice.org (k) Pike (l) reprepro (m) Tcl and (n) xgsmlib.