lib-src/movemail.c in movemail in emacs 22 and 23 allows local users to read, modify, or delete arbitrary mailbox files via a symlink attack, related to improper file-permission checks.
The hack-local-variables function in Emacs before 22.2, when enable-local-variables is set to :safe, does not properly search lists of unsafe or risky variables, which might allow user-assisted attackers to bypass intended restrictions and modify critical program variables via a file containing a Local variables declaration.