#VU48465 Use-after-free in Mozilla Firefox and Firefox ESR - CVE-2020-26960

Vulnerability identifier: #VU48465

Vulnerability risk: High

CVSSv4.0: 6.1 [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:U/U:Amber]

CVE-ID: CVE-2020-26960

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: No

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 compromise vulnerable system.

The vulnerability exists due to a use-after-free error within nsTArray implementation. If the Compact() method was called on an nsTArray, the array could have been reallocated without updating other pointers. A remote attacker can create a specially crafted web page, trick the victim into visiting it, 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.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Firefox: 60.0 - 82.0.3

Firefox ESR: 60.0 - 60.9.0, 68.0 - 68.12.0, 78.0 - 78.4.1

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
https://www.mozilla.org/en-US/security/advisories/mfsa2020-51/

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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?

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