Remote code execution in Mozilla Firefox and Firefox ESR

Published: 2019-06-18 | Updated: 2019-06-20
Risk Critical
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2019-11707
Exploitation vector Network
Public exploit This vulnerability is being exploited in the wild.
Vulnerable software
Firefox ESR
Client/Desktop applications / Web browsers

Mozilla Firefox
Client/Desktop applications / Web browsers

Vendor Mozilla

Security Bulletin

This security bulletin contains information about 1 vulnerabilities.

UPDATED 20.06.2019
Added information about additional vulnerability, exploited in the attack.

1) Type Confusion

EUVDB-ID: #VU18824

Risk: Critical

CVSSv3.1: 8.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2019-11707

CWE-ID: CWE-843 - Access of Resource Using Incompatible Type ('Type Confusion')

Exploit availability: Yes


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

The vulnerability exists due to a type confusion error when manipulating JavaScript objects due to issues in Array.pop. A remote attacker can create a specially crafted web page, 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 along with SB2019062002 (CVE-2019-11708).


Install updates from vendor's website.

Vulnerable software versions

Firefox ESR: 60.0, 60.0.1, 60.0.2, 60.1.0, 60.2.0, 60.2.1, 60.2.2, 60.3.0, 60.4.0, 60.5.0, 60.5.1, 60.5.2, 60.6.0, 60.6.1, 60.6.2, 60.6.3, 60.7.0

Mozilla Firefox: 61.0, 61.0.1, 61.0.2, 62.0, 62.0.1, 62.0.2, 62.0.3, 63.0, 63.0.1, 63.0.3, 64.0, 64.0.1, 64.0.2, 65.0, 65.0.1, 65.0.2, 66.0, 66.0.1, 66.0.2, 66.0.3, 66.0.4, 66.0.5, 67.0, 67.0.1, 67.0.2

CPE2.3 External links

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.