A total of 4 security vulnerabilities were addressed in the latest browser release, three of which were reported by external researchers.
The most important of the vulnerabilities are two High severity flaws that chain together to result in a sandbox escape. The issues include CVE-2018-6121, a privilege escalation in extensions, and CVE-2018-6122, a type confusion in V8.
The vulnerability chain was reported by an anonymous researcher on April 23. Google hasn’t published information on the flaw, but it appears that a remote attacker could exploit it to take control of vulnerable systems.
Another vulnerability resolved in the new browser iteration is CVE-2018-6120, a heap buffer overflow in PDFium reported by Zhou Aiting of Qihoo 360 Vulcan Team. The security researcher received a $5,000 reward for the finding.
The updated browser is available for download as version 66.0.3359.170 for Windows, Mac, and Linux devices.
This is the second time Google patches a Critical bug in Chrome 66 since the browser’s release in the stable channel less than a month ago.
In late April, the Internet giant addressed a use-after-free in Media Cache that could be exploited by a malicious actor to cause denial of service and possibly execute arbitrary code. The bug was reported by security researcher Ned Williamson, who received a $10,500 reward for the discovery.
The first stable release of Chrome 66 arrived with fixes for 62 security vulnerabilities, including two use after free in Disk Cache rated Critical severity (CVE-2018-6085 and CVE-2018-6086). Both issues were reported by Ned Williamson.