Security Experts:

Vulnerabilities Exploited at Chinese Hacking Contest Patched in Firefox, Chrome

Mozilla and Google have already patched the critical Firefox and Chrome vulnerabilities exploited recently by white hat hackers at a competition in China.

The Firefox vulnerability, tracked as CVE-2020-26950, has been described as an issue related to write side effects in MCallGetProperty opcode not being accounted for.

“In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition,” Mozilla said in an advisory published on Monday.

The flaw was fixed with the release of Firefox 82.0.3, Firefox ESR 78.4.1 and Thunderbird 78.4.2 just a couple of days after it was disclosed at the 2020 Tianfu Cup International PWN Contest, which took place over the past weekend in China.

As for the Chrome vulnerability disclosed at the Tianfu Cup, it’s tracked as CVE-2020-16016 and it has been described by Google as an inappropriate implementation issue in the base component. Google fixed it with an update released for Chrome 86 on Monday.

CVE-2020-26950 and CVE-2020-16016 were demonstrated by a team from Chinese cybersecurity firm Qihoo 360. This team earned over $740,000 of the total of $1.2 million awarded to participants at Tianfu Cup. For the Firefox vulnerability they earned $40,000, while for the Chrome flaw, which allowed them to achieve remote code execution with a sandbox escape, they received $100,000.

One of the Qihoo 360 researchers earned $20,000 from Google earlier this year for a sandbox escape vulnerability affecting Chrome.

 *updated last paragraph to clarify that only one of the Qihoo 360 researchers was credited for the discovery of the Chrome sandbox escape earlier this year

Related: VMware Patches ESXi Vulnerability That Earned Hacker $200,000

Related: Google Patches More High-Value Chrome Sandbox Escape Vulnerabilities

Related: Mozilla Patches Firefox Zero-Day Exploited in Targeted Attacks

Related: Firefox Flaw Allowed Hackers to Remotely Open Malicious Sites on Android Phones

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.