#VU53497 Use-after-free in macOS - CVE-2021-21779

Vulnerability identifier: #VU53497

Vulnerability risk: High

CVSSv4.0: 7.3 [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:P/U:Amber]

CVE-ID: CVE-2021-21779

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
macOS
Operating systems & Components / Operating system

Vendor: Apple Inc.

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error when processing HTML content in WebKit. A remote attacker can create a specially crafted web page, trick the victim into opening 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

macOS: 11.0 20A2411 - 11.3.1 20E241

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External links
https://support.apple.com/en-us/HT212529
https://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1238

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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. However, proof of concept for this vulnerability is available.