Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability. This update upgrades Firefox to version 91.5.0 ESR. Security Fix: * Mozilla: Iframe sandbox bypass with XSLT * Mozilla: Race condition when playing audio files * Mozilla: Heap-buffer-overflow in blendGaussianBlur * Mozilla: Use-after-free of ChannelEventQueue::mOwner * Mozilla: Browser window spoof using fullscreen mode * Mozilla: Out-of-bounds memory access when inserting text in edit mode * Mozilla: Browser window spoof using fullscreen mode * Mozilla: Memory safety bugs fixed in Firefox 96 and Firefox ESR 91.5 * Mozilla: Leaking cross-origin URLs through securitypolicyviolation event * Mozilla: Spoofed origin on external protocol launch dialog * Mozilla: Missing throttling on external protocol launch dialog * Mozilla: Crash when handling empty pkcs7 sequence For more details about the security issue, including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page listed in the References section.