RHSA-2021:3755 — Security Advisory

Red Hat Security Advisory: firefox security update

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Severity

Important

Red Hat Product Security

RHEL 8

Products

Official CSAF product identity

Published · October 11, 2021

Updated · November 22, 2025

Topic

An update for firefox is now available for Red Hat Enterprise Linux 8.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability.

This update upgrades Firefox to version 91.2.0 ESR.

Security Fix(es):

  • Mozilla: Use-after-free in MessageTask (CVE-2021-38496)

  • Mozilla: Memory safety bugs fixed in Firefox 93, Firefox ESR 78.15, and Firefox ESR 91.2 (CVE-2021-38500)

  • Mozilla: Memory safety bugs fixed in Firefox 93 and Firefox ESR 91.2 (CVE-2021-38501)

  • rust-crossbeam-deque: race condition may lead to double free (CVE-2021-32810)

  • Mozilla: Validation message could have been overlaid on another origin (CVE-2021-38497)

  • Mozilla: Use-after-free of nsLanguageAtomService object (CVE-2021-38498)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Related CVEs

RHSA-2021:3755 — Red Hat Security Advisory: firefox security update | PulseLinux