This vulnerability was used along with CVE-2019-11707 in a targeted attack against Conbase.
Vulnerable component: Mozilla Firefox
CVSSv3 score: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C
CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls
The vulnerability allows a remote attacker to bypass sandbox restrictions.
The vulnerability exists due to insufficient vetting of parameters passed with the
IPC message between child and parent processes. A remote attacker can create a specially crafted web page that can make the non-sandboxed parent process open web content chosen by a compromised child process.
An attacker can combine this behavior along with another vulnerability to execute arbitrary code on the system with privileges on the current user.
Note, this vulnerability is being exploited in the wild along with SB2019061805 (CVE-2019-11707)