Red Hat Product Errata RHSA-2026:13537 - Security Advisory Issued: 2026-05-04 Updated: 2026-05-04 RHSA-2026:13537 - Security Advisory Overview Updated Packages Synopsis Important: thunderbird 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 thunderbird 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 Thunderbird is a standalone mail and newsgroup client. 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 8 x86_64 Red Hat Enterprise Linux for IBM z Systems 8 s390x Red Hat Enterprise Linux for Power, little endian 8 ppc64le Red Hat Enterprise Linux for ARM 64 8 aarch64 Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 8.10 x86_64 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 8.10 aarch64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 8.10 ppc64le Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 8.10 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 8 SRPM thunderbird-140.10.0-1.el8_10.src.rpm SHA-256: d0ff84a1fb71c061bfb2907e945496ed73530093c5e6d5dbe33faf83b0172427 x86_64 thunderbird-140.10.0-1.el8_10.x86_64.rpm SHA-256: e243a9a27ecadb65001afa146020e02cd6f3a50422c3cfac82b58cb1b72fc78e thunderbird-debuginfo-140.10.0-1.el8_10.x86_64.rpm SHA-256: 9df14cd7d82c95c9a4a5b69763f93ae03ab00dcaeaee38e25863e194deaa895c thunderbird-debugsource-140.10.0-1.el8_10.x86_64.rpm SHA-256: 2ddac6241b6ee837a28f9f8e514057760faf8c80dc5a1622e4ced9aebb2b7041 Red Hat Enterprise Linux for IBM z Systems 8 SRPM thunderbird-140.10.0-1.el8_10.src.rpm SHA-256: d0ff84a1fb71c061bfb2907e945496ed73530093c5e6d5dbe33faf83b0172427 s390x thunderbird-140.10.0-1.el8_10.s390x.rpm SHA-256: 054252808405e4246424211ca0aba796a4a2201cb5f40fce86a267a4ec5733aa thunderbird-debuginfo-140.10.0-1.el8_10.s390x.rpm SHA-256: 57211f69fb7fd5d2e60649cc2cb3682e3b44fd6f53f9f76f0cf9b0bdc10cdd1b thunderbird-debugsource-140.10.0-1.el8_10.s390x.rpm SHA-256: f54c5d4bd72c4138f5330dedf275e444af92d430546ec309035e0685a684089a Red Hat Enterprise Linux for Power, little endian 8 SRPM thunderbird-140.10.0-1.el8_10.src.rpm SHA-256: d0ff84a1fb71c061bfb2907e945496ed73530093c5e6d5dbe33faf83b0172427 ppc64le thunderbird-140.10.0-1.el8_10.ppc64le.rpm SHA-256: 50717124141e09eb56ef01fff039454369e3c848f3a0d85cf1b105bb4588f9c9 thunderbird-debuginfo-140.10.0-1.el8_10.ppc64le.rpm SHA-256: e3cf2afd69de4262779a6c68699a6239127206cf30419371a4c9c63e9032e738 thunderbird-debugsource-140.10.0-1.el8_10.ppc64le.rpm SHA-256: 145e562d2ca16c79b28dfc78fe37a6d0e31bd6ef2a81901ca9bdec702e92317b Red Hat Enterprise Linux for ARM 64 8 SRPM thunderbird-140.10.0-1.el8_10.src.rpm SHA-256: d0ff84a1fb71c061bfb2907e945496ed73530093c5e6d5dbe33faf83b0172427 aarch64 thunderbird-140.10.0-1.el8_10.aarch64.rpm SHA-256: 374c4f63366d671b90fdcea7e70728e00abcfe6b28d3459ae40d50f5cdd3cf5c thunderbird-debuginfo-140.10.0-1.el8_10.aarch64.rpm SHA-256: 83e8b08dcffd5c63a0a4e6d3c64035f51193480e663959bd3bb281190492d248 thunderbird-debugsource-140.10.0-1.el8_10.aarch64.rpm SHA-256: 99d5da6f980db404df5c6fb833f46a97d5b260b64c2877eb46241e3907e53319 Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 8.10 SRPM thunderbird-140.10.0-1.el8_10.src.rpm SHA-256: d0ff84a1fb71c061bfb2907e945496ed73530093c5e6d5dbe33faf83b0172427 x86_64 thunderbird-140.10.0-1.el8_10.x86_64.rpm SHA-256: e243a9a27ecadb65001afa146020e02cd6f3a50422c3cfac82b58cb1b72fc78e thunderbird-debuginfo-140.10.0-1.el8_10.x86_64.rpm SHA-256: 9df14cd7d82c95c9a4a5b69763f93ae03ab00dcaeaee38e2586