#VU24147 Type Confusion in Mozilla Firefox and Firefox ESR - CVE-2019-17026

Vulnerability identifier: #VU24147

Vulnerability risk: Critical

CVSSv4.0: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red]

CVE-ID: CVE-2019-17026

CWE-ID: CWE-843

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Mozilla Firefox
Client/Desktop applications / Web browsers
Firefox ESR
Client/Desktop applications / Web browsers

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a type confusion error with StoreElementHole and FallibleStoreElement when processing HTML content in IonMonkey JIT compiler. A remote attacker can create a specially crafted webpage, trick the victim into visiting it, trigger a type confusion error and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Note, this vulnerability is being actively exploited in the wild.

Mitigation
Update to Firefox 72.0.1 or Firefox ESR 68.4.1.

Vulnerable software versions

Mozilla Firefox: 65.0 - 72.0

Firefox ESR: 60.0 - 60.9.0, 68.0 - 68.4.0

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2020-03/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.