Hard link and possibly symbolic link following vulnerabilities in QNX RTOS 4.25 (aka QNX4) allow local users to overwrite arbitrary files via (1) the -f argument to the monitor utility, (2) the -d argument to dumper, (3) the -c argument to crttrap, or (4) using the Watcom sample utility.
Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:NI:HA:N5.5/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N