GNU ed before 0.3 allows local users to overwrite arbitrary files via a symlink attack on temporary files, possibly in the open_sbuf function.
https://issues.rpath.com/browse/RPL-962
https://exchange.xforce.ibmcloud.com/vulnerabilities/30374
http://www.vupen.com/english/advisories/2006/4573
http://www.trustix.org/errata/2007/0005
http://www.securityfocus.com/bid/22129
http://www.mandriva.com/security/advisories?name=MDKSA-2007:023
http://secunia.com/advisories/24054
http://secunia.com/advisories/23857
http://secunia.com/advisories/23848
http://secunia.com/advisories/23832
http://freshmeat.net/projects/ed/?branch_id=17855&release_id=240890