Versions of the IBM Notes email and workgroup software package contains a security vulnerability that could allow an attacker to gain control of a victim's computer or install software without them noticing.
The problem affects versions 8.0.x, 8.5.x, and 9.0 of Notes, IBM confirmed on its security bulletin pages.
IBM classified the problem with a CVSS score of 4.3 out of 10, meaning that it thinks it is critical.
It has issued interim fixes — Interim Fix 1 for Notes 8.5.3 Fix Pack 4 and Interim Fix 1 for Notes 9.0 — for the Windows versions of its software while it works on a permanent solution.
IBM said a fix for Mac machines is also forthcoming.
Linux users are advised to "monitor fix availability in 8.5.3 Fix Pack 5 and 9.0.1" or to inquire about the possibility of obtaining a fix sooner by raising a support request ticket.
IBM also detailed a workaround for users that would rather not wait for a fix to be issued.