Red Hat Product Errata RHSA-2026:19463 - Security Advisory Issued: 2026-05-20 Updated: 2026-05-20 RHSA-2026:19463 - 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 10.0 Extended 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 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 - Extended Update Support 10.0 x86_64 Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.0 s390x Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.0 ppc64le Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.0 aarch64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.0 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 10.0 s390x Red Hat Enterprise Linux for Power, little endian - 4 years of support 10.0 ppc64le Red Hat Enterprise Linux for x86_64 - 4 years of updates 10.0 x86_64 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 10.0 SRPM thunderbird-140.10.0-1.el10_0.src.rpm SHA-256: 556e9ef33eb3d9644d8aeff21671e5046196611e0e877d853c0f3cbb6a969a2e x86_64 thunderbird-140.10.0-1.el10_0.x86_64.rpm SHA-256: 31614035385716c25b7b48550289b0eb3eb3c2638a055779720e51bf89ea2ee0 thunderbird-debuginfo-140.10.0-1.el10_0.x86_64.rpm SHA-256: 098eb0725be72ef004c257972fc474f4d36ee2936d60f819b34d7d0177559df7 thunderbird-debugsource-140.10.0-1.el10_0.x86_64.rpm SHA-256: 9dd5342432934081118a729146922ed06a3f2f88c0b69f89ee8912633ee0ae3b Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.0 SRPM thunderbird-140.10.0-1.el10_0.src.rpm SHA-256: 556e9ef33eb3d9644d8aeff21671e5046196611e0e877d853c0f3cbb6a969a2e s390x thunderbird-140.10.0-1.el10_0.s390x.rpm SHA-256: 510ee4a1384deb0403bdee3d17372e21a3ac1e4d748dfe02f74114b3f1af1570 thunderbird-debuginfo-140.10.0-1.el10_0.s390x.rpm SHA-256: 75bbba5677952f0fb0158ff92f0acb1691b05161e55afd67cb2ca3e1c9526672 thunderbird-debugsource-140.10.0-1.el10_0.s390x.rpm SHA-256: 0bd110821ee3d3fc9bf7864f9c3851e37d8df81502202c2b2f8a4cc9fb2e851a Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.0 SRPM thunderbird-140.10.0-1.el10_0.src.rpm SHA-256: 556e9ef33eb3d9644d8aeff21671e5046196611e0e877d853c0f3cbb6a969a2e ppc64le thunderbird-140.10.0-1.el10_0.ppc64le.rpm SHA-256: d2e8b7b3b6fe15057697d4c1958e6d48350bb232c0bd2c24e4549da61019a3fa thunderbird-debuginfo-140.10.0-1.el10_0.ppc64le.rpm SHA-256: 85b51687f95b70fe86a7af5a1fa9218c7d30d14fcb91bf01d687dd5e894f6e94 thunderbird-debugsource-140.10.0-1.el10_0.ppc64le.rpm SHA-256: cc3d72372d2386dc9f5e2f6fd3a24536f1ad74aefae7763e56dc457499b65ece Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.0 SRPM thunderbird-140.10.0-1.el10_0.src.rpm SHA-256: 556e9ef33eb3d9644d8aeff21671e5046196611e0e877d853c0f3cbb6a969a2e aarch64 thunderbird-140.10.0-1.el10_0.aarch64.rpm SHA-256: 9df20eab2e6b3dea63c3fabc86e5c34f7d324aeb0fc04f61a4a05e5cb5e544a4 thunderbird-debuginfo-140.10.0-1.el10_0.aarch64.rpm SHA-256: 19c0b2dc85a129b7447b2c437b1ca4d5c73e4d4a41cc4005b52c7e13b8966fec thunderbird-debugsource-140.10.0-1.el10_0.aarch64.rpm SHA-256: e10ae1a4aa5e736cbe4a97bddbdbf9338e167dcbf7f33ca7c23376c32a89cb5a Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.0 SRPM thunderbird-140.10.0-1.el10_0.src.rpm SHA-256: 556e9ef33eb3d9644d8aeff21671e5046196611e0e87