Emergency Firefox Update Patches Two Actively Exploited Zero-Day Vulnerabilities

Mozilla over the weekend issued an emergency security update for Firefox to address two zero-day vulnerabilities that have been exploited in attacks.

Tracked as CVE-2022-26485 and CVE-2022-26486 and rated “critical severity,” the two security holes are use-after-free issues that were discovered and reported by security researchers with Qihoo 360 ATA.

The first of the vulnerabilities can be triggered by removing an Extensible Stylesheet Language Transformations (XSLT) parameter during processing, while the second bug is triggered by an unexpected message in the WebGPU inter-process communication (IPC) framework.

“We have had reports of attacks in the wild abusing this flaw,” Mozilla notes in its advisory.

While the browser maker did not provide further details on the observed exploitation attempts, use-after-free vulnerabilities typically allow attackers to execute arbitrary code on target systems.

Both issues were resolved with the release of Firefox 97.0.2, Firefox ESR 91.6.1, Firefox for Android 97.3.0, and Focus 97.3.0, Mozilla says.

Technical details on the two security holes haven’t been shared either, but more information will likely be released once the majority of users have installed the patches.

Over the past two years, Firefox has been mostly spared from zero-day attacks, despite the identification and patching of tens of severe vulnerabilities in the browser during this time.

Google Project Zero has tracked seven Firefox vulnerabilities that have been exploited in attacks since 2014, including two patched in 2020, three in 2019, one in 2016, and one in 2015.

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