Remote code execution in Mozilla Firefox

Published: 2021-01-06 | Updated: 2021-07-01
Risk High
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-16044
Exploitation vector Network
Public exploit N/A
Vulnerable software
Mozilla Firefox
Client/Desktop applications / Web browsers

Firefox ESR
Client/Desktop applications / Web browsers

Firefox for Android
Mobile applications / Apps for mobile phones

Vendor Mozilla

Security Bulletin

This security bulletin contains one high risk vulnerability.

1) Use-after-free

EUVDB-ID: #VU49300

Risk: High

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-16044

CWE-ID: CWE-416 - Use After Free

Exploit availability: No


The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error when processing COOKIE-ECHO chunk in a SCTP packet. A remote attacker can pass specially crafted data to the browser, trigger a use-after-free error and execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.


Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 6.0.1 - 84.0.1

Firefox ESR: 60.0 - 78.6.0

Firefox for Android: 66.0.4 - 84.1.2

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?

No. We are not aware of malware exploiting this vulnerability.