This Important Red Hat advisory addresses multiple critical vulnerabilities in Firefox for RHEL 8.2 AUS, including a libpng use-after-free (CVE-2026-33416, CVSS 7.5) allowing arbitrary code execution, an out-of-bounds read/write in libpng (CVE-2026-33636, CVSS 7.6), and critical memory safety bugs (CVE-2026-5734, CVSS 9.8). Affected Firefox versions are prior to 140.9.1 or 149.0.2, and affected libpng versions are from 1.6.36 to prior to 1.6.56. The fix is applied via the Red Hat package update described in the advisory.
Red Hat Product Errata RHSA-2026:11805 - Security Advisory Issued: 2026-04-29 Updated: 2026-04-29 RHSA-2026:11805 - Security Advisory Overview Updated Packages Synopsis Important: firefox security update Type/Severity Security Advisory: Important Red Hat Lightspeed patch analysis Identify and remediate systems affected by this advisory. View affected systems Topic An update for firefox is now available for Red Hat Enterprise Linux 8.2 Advanced Update Support. 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. Security Fix(es): libpng: libpng: Arbitrary code execution due to use-after-free vulnerability (CVE-2026-33416) libpng: libpng: Information disclosure and denial of service via out-of-bounds read/write in Neon palette expansion (CVE-2026-33636) thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 (CVE-2026-5734) thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 (CVE-2026-5731) firefox: thunderbird: Incorrect boundary conditions, integer overflow in the Graphics: Text component (CVE-2026-5732) 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. Solution For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Affected Products Red Hat Enterprise Linux Server - AUS 8.2 x86_64 Fixes BZ - 2451805 - CVE-2026-33416 libpng: libpng: Arbitrary code execution due to use-after-free vulnerability BZ - 2451819 - CVE-2026-33636 libpng: libpng: Information disclosure and denial of service via out-of-bounds read/write in Neon palette expansion BZ - 2455897 - CVE-2026-5734 thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 BZ - 2455901 - CVE-2026-5731 thunderbird: firefox: Memory safety bugs fixed in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2 BZ - 2455908 - CVE-2026-5732 firefox: thunderbird: Incorrect boundary conditions, integer overflow in the Graphics: Text component CVEs CVE-2026-5731 CVE-2026-5732 CVE-2026-5734 CVE-2026-33416 CVE-2026-33636 References https://access.redhat.com/security/updates/classification/#important Note: More recent versions of these packages may be available. Click a package name for more details. Red Hat Enterprise Linux Server - AUS 8.2 SRPM firefox-140.9.1-1.el8_2.src.rpm SHA-256: aaae5632ae49af31a1fc9012492b698be263373a1b1bf93d10d17f69f1d42f25 x86_64 firefox-140.9.1-1.el8_2.x86_64.rpm SHA-256: 05b93a7da95947fe6ac0f5c9c1559fc6bbe806ac7c1ca7f96737f7cd79c8a274 firefox-debuginfo-140.9.1-1.el8_2.x86_64.rpm SHA-256: d15ab9a1141dbe9b1c6b7b9b712eb3c1c130e3dc821384d5c07b95a739951991 firefox-debugsource-140.9.1-1.el8_2.x86_64.rpm SHA-256: 037dacaee4d1bab20f12dfa9276cf947fb56b095f6fb91f35bfb6ea60a6d3c8d The Red Hat security contact is secalert@redhat.com . More contact details at https://access.redhat.com/security/team/contact/ .