transports/appendfile.c in Exim before 4.72, when a world-writable sticky-bit mail directory is used, does not verify the st_nlink field of mailbox files, which allows local users to cause a denial of service or possibly gain privileges by creating a hard link to another user’s file.
archives.neohapsis.com/archives/fulldisclosure/2010-06/0079.html
bugs.exim.org/show_bug.cgi?id=988
lists.exim.org/lurker/message/20100524.175925.9a69f755.en.html
lists.fedoraproject.org/pipermail/package-announce/2010-June/042587.html
lists.fedoraproject.org/pipermail/package-announce/2010-June/042613.html
lists.opensuse.org/opensuse-security-announce/2010-08/msg00001.html
secunia.com/advisories/40019
secunia.com/advisories/40123
secunia.com/advisories/43243
vcs.exim.org/viewvc/exim/exim-doc/doc-txt/ChangeLog?view=markup&pathrev=exim-4_72_RC2
vcs.exim.org/viewvc/exim/exim-src/src/transports/appendfile.c?r1=1.24&r2=1.25
www.securityfocus.com/archive/1/511653/100/0/threaded
www.securityfocus.com/bid/40451
www.ubuntu.com/usn/USN-1060-1
www.vupen.com/english/advisories/2010/1402
www.vupen.com/english/advisories/2011/0364
bugzilla.redhat.com/show_bug.cgi?id=600093
exchange.xforce.ibmcloud.com/vulnerabilities/59043