Red Hat Product Errata RHSA-2026:19464 - Security Advisory Issued: 2026-05-20 Updated: 2026-05-20 RHSA-2026:19464 - 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 9.4 Update Services for SAP Solutions. 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): firefox: thunderbird: Incorrect boundary conditions in the Libraries component in NSS (CVE-2026-6772) firefox: thunderbird: Use-after-free in the JavaScript Engine component (CVE-2026-6754) firefox: thunderbird: Spoofing issue in the DOM: Core & HTML component (CVE-2026-6762) firefox: thunderbird: Incorrect boundary conditions in the WebRTC component (CVE-2026-6752) firefox: thunderbird: Other issue in the Storage: IndexedDB component (CVE-2026-6770) firefox: thunderbird: Invalid pointer in the JavaScript: WebAssembly component (CVE-2026-6757) firefox: thunderbird: Other issue in the Libraries component in NSS (CVE-2026-6767) firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150 (CVE-2026-6786) firefox: thunderbird: Incorrect boundary conditions in the WebRTC component (CVE-2026-6753) firefox: thunderbird: Use-after-free in the Widget: Cocoa component (CVE-2026-6759) firefox: thunderbird: Use-after-free in the WebRTC component (CVE-2026-6747) firefox: thunderbird: Information disclosure due to uninitialized memory in the Graphics: Canvas2D component (CVE-2026-6749) firefox: thunderbird: Incorrect boundary conditions in the Libraries component in NSS (CVE-2026-6766) firefox: thunderbird: Privilege escalation in the Networking component (CVE-2026-6761) firefox: thunderbird: Mitigation bypass in the File Handling component (CVE-2026-6763) firefox: thunderbird: Privilege escalation in the Graphics: WebRender component (CVE-2026-6750) firefox: thunderbird: Uninitialized memory in the Audio/Video: Web Codecs component (CVE-2026-6748) firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150 (CVE-2026-6785) firefox: thunderbird: Mitigation bypass in the DOM: Security component (CVE-2026-6771) firefox: thunderbird: Incorrect boundary conditions in the DOM: Device Interfaces component (CVE-2026-6764) firefox: thunderbird: Information disclosure in the Form Autofill component (CVE-2026-6765) firefox: thunderbird: Privilege escalation in the Debugger component (CVE-2026-6769) firefox: thunderbird: Uninitialized memory in the Audio/Video: Web Codecs component (CVE-2026-6751) firefox: thunderbird: Incorrect boundary conditions in the WebRTC: Networking component (CVE-2026-6776) firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-6746) 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 for x86_64 - Extended Update Support 9.4 x86_64 Red Hat Enterprise Linux Server - AUS 9.4 x86_64 Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.4 s390x Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.4 ppc64le Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.4 aarch64 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.4 ppc64le Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.4 x86_64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.4 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.4 s390x Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.4 x86_64 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.4 aarch64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.4 ppc64le Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 9.4 s390x Fixes BZ - 2460074 - CVE-2026-6772 firefox: thunderbird: Incorrect boundary conditions in the Libraries component in NSS BZ - 2460075 - CVE-2026-6754 firefox: thunderbird: Use-after-free in the JavaScript Engine component BZ - 2460076 - CVE-2026-6762 firefox: thunderbird: Spoofing issue in the DOM: Core & HTML component BZ - 2460078 - CVE-2026-6752 firefox: thunderbird: Incorrect boundary conditions in the WebRTC component BZ - 2460079 - CVE-2026-6770 firefox: thunderbird: Other issue in the Storage: IndexedDB component BZ - 2460085 - CVE-2026-6757 firefox: thunderbird: Invalid pointer in the JavaScript: WebAssembly component BZ - 2460086 - CVE-2026-6767 firefox: thunderbird: Other issue in the Libraries component in NSS BZ - 2460088 - CVE-2026-6786 firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150 BZ - 2460092 - CVE-2026-6753 firefox: thunderbird: Incorrect boundary conditions in the WebRTC component BZ - 2460094 - CVE-2026-6759 firefox: thunderbird: Use-after-free in the Widget: Cocoa component BZ - 2460095 - CVE-2026-6747 firefox: thunderbird: Use-after-free in the WebRTC component BZ - 2460096 - CVE-2026-6749 firefox: thunderbird: Information disclosure due to uninitialized memory in the Graphics: Canvas2D component BZ - 2460097 - CVE-2026-6766 firefox: thunderbird: Incorrect boundary conditions in the Libraries component in NSS BZ - 2460099 - CVE-2026-6761 firefox: thunderbird: Privilege escalation in the Networking component BZ - 2460101 - CVE-2026-6763 firefox: thunderbird: Mitigation bypass in the File Handling component BZ - 2460102 - CVE-2026-6750 firefox: thunderbird: Privilege escalation in the Graphics: WebRender component BZ - 2460103 - CVE-2026-6748 firefox: thunderbird: Uninitialized memory in the Audio/Video: Web Codecs component BZ - 2460104 - CVE-2026-6785 firefox: thunderbird: Memory safety bugs fixed in Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird ESR 140.10, Firefox 150 and Thunderbird 150 BZ - 2460105 - CVE-2026-6771 firefox: thunderbird: Mitigation bypass in the DOM: Security component BZ - 2460106 - CVE-2026-6764 firefox: thunderbird: Incorrect boundary conditions in the DOM: Device Interfaces component BZ - 2460107 - CVE-2026-6765 firefox: thunderbird: Information disclosure in the Form Autofill component BZ - 2460108 - CVE-2026-6769 firefox: thunderbird: Privilege escalation in the Debugger component BZ - 2460109 - CVE-2026-6751 firefox: thunderbird: Uninitialized memory in the Audio/Video: Web Codecs component BZ - 2460110 - CVE-2026-6776 firefox: thunderbird: Incorrect boundary conditions in the WebRTC: Networking component BZ - 2460112 - CVE-2026-6746 firefox: thunderbird: Use-after-free in the DOM: Core & HTML component CVEs CVE-2026-6746 CVE-2026-6747 CVE-2026-6748 CVE-2026-6749 CVE-2026-6750 CVE-2026-6751 CVE-2026-6752 CVE-2026-6753 CVE-2026-6754 CVE-2026-6757 CVE-2026-6759 CVE-2026-6761 CVE-2026-6762 CVE-2026-6763 CVE-2026-6764 CVE-2026-6765 CVE-2026-6766 CVE-2026-6767 CVE-2026-6769 CVE-2026-6770 CVE-2026-6771 CVE-2026-6772 CVE-2026-6776 CVE-2026-6785 CVE-2026-6786 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 for x86_64 - Extended Update Support 9.4 SRPM firefox-140.10.0-1.el9_4.src.rpm SHA-256: 6ff39b094300d457d29b56d00c1b17161afee19e9cdc6b4f17a82a174935f290 x86_64 firefox-140.10.0-1.el9_4.x86_64.rpm SHA-256: 7157779ab1b7da8e030cd2534508b72ff3dc082cc924fec3a0c4e2533fe4e737 firefox-debuginfo-140.10.0-1.el9_4.x86_64.rpm SHA-256: 31e21a87ee9f20258b51570cc8b680c57c2ab4c7717519d3a672a2b005576b19 firefox-debugsource-140.10.0-1.el9_4.x86_64.rpm SHA-256: 4ad4642d7447e7ec12a66cafe8a4e94bb329942b88e215de7703357084dff491 firefox-x11-140.10.0-1.el9_4.x86_64.rpm SHA-256: 556cfd4ea548f9a3a3eacd9a0d9dc8d96f2c8b8d38e01647c156df5923c72a96 Red Hat Enterprise Linux Server - AUS 9.4 SRPM firefox-140.10.0-1.el9_4.src.rpm SHA-256: 6ff39b094300d457d29b56d00c1b17161afee19e9cdc6b4f17a82a174935f290 x86_64 firefox-140.10.0-1.el9_4.x86_64.rpm SHA-256: 7157779ab1b7da8e030cd2534508b72ff3dc082cc924fec3a0c4e2533fe4e737 firefox-debuginfo-140.10.0-1.el9_4.x86_64.rpm SHA-256: 31e21a87ee9f20258b51570cc8b680c57c2ab4c7717519d3a672a2b005576b19 firefox-debugsource-140.10.0-1.el9_4.x86_64.rpm SHA-256: 4ad4642d7447e7ec12a66cafe8a4e94bb329942b88e215de7703357084dff491 firefox-x11-140.10.0-1.el9_4.x86_64.rpm SHA-256: 556cfd4ea548f9a3a3eacd9a0d9dc8d96f2c8b8d38e01647c156df5923c72a96 Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.4 SRPM firefox-140.10.0-1.el9_4.src.rpm SHA-256: 6ff39b094300d457d29b56d00c1b17161afee19e9cdc6b4f17a82a174935f290 s390x firefox-140.10.0-1.el9_4.s390x.rpm SHA-256: 1f1c7ccbd66224550eb502b2f33fca27822b3e1ed9fab717b6f9a5062afba1fc firefox-debuginfo-140.10.0-1.el9_4.s390x.rpm SHA-256: d90bc6a57598827ecbbe5db94a9e0ae28b3452366d1d034c6251ca3c11ccc3de firefox-debugsource-140.10.0-1.el9_4.s390x.rpm SHA-256: 17fa3e33487791be0f03bedfe2c044c791b714e4b634fd464368a1fd693542dc firefox-x11-140.10.0-1.el9_4.s390x.rpm SHA-256: b179261e6a25f917ea0991d9a65cee3895473b20abbb5a66e69e95cf0f1deff5 Red Hat Enterprise Linux for Power, little endian - Extended Update Su
This security update addresses multiple vulnerabilities in Firefox and Thunderbird, including high-severity use-after-free and memory safety bugs (e.g., CVE-2026-6754, CVSS 7.5) that can lead to remote code execution or privilege escalation. Affected versions include Firefox < 115.35.0, Firefox < 150.0, Firefox >= 140.0 < 140.10.0, and Thunderbird < 140.10.0. The fix requires updating to Firefox 115.35.0, 150.0, or 140.10.0, and Thunderbird 140.10.0, as specified per CVE.