The runtime linker in QNX Neutrino RTOS 6.5.0 before Service Pack 1 does not properly clear the LD_DEBUG_OUTPUT and LD_DEBUG environment variables when a program is spawned from a setuid program, which allows local users to overwrite files via a symlink attack.
http://www.securityfocus.com/bid/46838
http://www.securityfocus.com/archive/1/518659
http://www.securityfocus.com/archive/1/516958
http://www.qnx.com/developers/articles/rel_5189_46.html