This Red Hat security advisory addresses multiple vulnerabilities in Thunderbird, including a critical sandbox escape in the Profile Backup component (CVE-2026-8401, CVSS 9.8), a high-severity JIT boundary condition flaw (CVE-2026-8388, CVSS 6.5), and other issues ranging from privilege escalation to denial-of-service. Based on the provided NVD data, affected versions are Mozilla Firefox (and by extension Thunderbird) prior to version 150.0.3. The fix is to apply the Red Hat-provided Thunderbird update for RHEL 8, which incorporates the upstream patches.
Red Hat Product Errata RHSA-2026:22643 - Security Advisory Issued: 2026-06-02 Updated: 2026-06-02 RHSA-2026:22643 - 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: Incorrect boundary conditions in the JavaScript Engine: JIT component (CVE-2026-8388) firefox: Other issue in the JavaScript Engine component (CVE-2026-8391) firefox: Sandbox escape in the Profile Backup component (CVE-2026-8401) firefox: Integer overflow in the Networking: JAR component (CVE-2026-8956) firefox: Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151 (CVE-2026-8975) firefox: Privilege escalation in the DOM: Workers component (CVE-2026-8955) firefox: Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component (CVE-2026-8968) firefox: Incorrect boundary conditions, integer overflow in the Audio/Video component (CVE-2026-8954) firefox: Information disclosure, sandbox escape in the Security: Process Sandboxing component (CVE-2026-8958) firefox: Incorrect boundary conditions in the Audio/Video: Web Codecs component (CVE-2026-8946) firefox: Privilege escalation in the Security component (CVE-2026-8970) firefox: Same-origin policy bypass in the Networking: HTTP component (CVE-2026-8950) firefox: Memory safety bugs fixed in Firefox ESR 140.11 and Firefox 151 (CVE-2026-8974) firefox: Sandbox escape due to use-after-free in the Disability Access APIs component (CVE-2026-8953) firefox: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component (CVE-2026-8959) firefox: Spoofing issue in the Form Autofill component (CVE-2026-8961) firefox: Use-after-free in the DOM: Bindings (WebIDL) component (CVE-2026-8947) firefox: Mitigation bypass in the DOM: Security component (CVE-2026-8962) firefox: Privilege escalation in the Enterprise Policies component (CVE-2026-8957) 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 - 2476469 - CVE-2026-8388 firefox: thunderbird: Incorrect boundary conditions in the JavaScript Engine: JIT component BZ - 2476475 - CVE-2026-8391 firefox: thunderbird: Other issue in the JavaScript Engine component BZ - 2476492 - CVE-2026-8401 firefox: thunderbird: Sandbox escape in the Profile Backup component BZ - 2479839 - CVE-2026-8956 firefox: Integer overflow in the Networking: JAR component BZ - 2479840 - CVE-2026-8975 firefox: Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151 BZ - 2479842 - CVE-2026-8955 firefox: thunderbird: Privilege escalation in the DOM: Workers component BZ - 2479846 - CVE-2026-8968 firefox: Denial-of-service due to invalid pointer in the Audio/Video: Web Codecs component BZ - 2479847 - CVE-2026-8954 firefox: Incorrect boundary conditions, integer overflow in the Audio/Video component BZ - 2479848 - CVE-2026-8958 firefox: Information disclosure, sandbox escape in the Security: Process Sandboxing component BZ - 2479849 - CVE-2026-8946 firefox: thunderbird: Incorrect boundary conditions in the Audio/Video: Web Codecs component BZ - 2479852 - CVE-2026-8970 firefox: Privilege escalation in the Security component BZ - 2479853 - CVE-2026-8950 firefox: Same-origin policy bypass in the Networking: HTTP component BZ - 2479855 - CVE-2026-8974 firefox: Memory safety bugs fixed in Firefox ESR 140.11 and Firefox 151 BZ - 2479860 - CVE-2026-8953 firefox: Sandbox escape due to use-after-free in the Disability Access APIs component BZ - 2479861 - CVE-2026-8959 firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component BZ - 2479871 - CVE-2026-8961 firefox: Spoofing issue in the Form Autofill component BZ - 2479873 - CVE-2026-8947 firefox: thunderbird: Use-after-free in the DOM: Bindings (WebIDL) component BZ - 2479876 - CVE-2026-8962 firefox: Mitigation bypass in the DOM: Security component BZ - 2479880 - CVE-2026-8957 firefox: Privilege escalation in the Enterprise Policies component CVEs CVE-2026-8388 CVE-2026-8391 CVE-2026-8401 CVE-2026-8946 CVE-2026-8947 CVE-2026-8950 CVE-2026-8953 CVE-2026-8954 CVE-2026-8955 CVE-2026-8956 CVE-2026-8957 CVE-2026-8958 CVE-2026-8959 CVE-2026-8961 CVE-2026-8962 CVE-2026-8968 CVE-2026-8970 CVE-2026-8974 CVE-2026-8975 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-140.11.0-1.el8_10.src.rpm SHA-256: b110738c866c4a864c3d2850dda33f224af3ac8a0c9dae5aa64cf9685a7418b4 x86_64 thunderbird-140.11.0-1.el8_10.x86_64.rpm SHA-256: 7a7b2d592387a48de2f1d994acb94f288df4fdb3d1abc0650fe9b8f68fe1a43a thunderbird-debuginfo-140.11.0-1.el8_10.x86_64.rpm SHA-256: 278f7dc73efddfca5af4de20a7deb9b5a11ce01725f5a22390e2e962e9e243c6 thunderbird-debugsource-140.11.0-1.el8_10.x86_64.rpm SHA-256: e9a19da76265d07d94f26008793020662d9c54d7594c9b3b7e7931310f20583d Red Hat Enterprise Linux for IBM z Systems 8 SRPM thunderbird-140.11.0-1.el8_10.src.rpm SHA-256: b110738c866c4a864c3d2850dda33f224af3ac8a0c9dae5aa64cf9685a7418b4 s390x thunderbird-140.11.0-1.el8_10.s390x.rpm SHA-256: 06498c31c4bf50b1747f107aaed58d3749cbad3b7dd62ed29145722c3999e8a7 thunderbird-debuginfo-140.11.0-1.el8_10.s390x.rpm SHA-256: 1477480676c8e62b9c480bd19216d35f390da62633ebdbac28ad968bae537b47 thunderbird-debugsource-140.11.0-1.el8_10.s390x.rpm SHA-256: 5fa37db27e2e6939eab183cd95b2fbf8b9f27bd42762208c22be62297e4b3c88 Red Hat Enterprise Linux for Power, little endian 8 SRPM thunderbird-140.11.0-1.el8_10.src.rpm SHA-256: b110738c866c4a864c3d2850dda33f224af3ac8a0c9dae5aa64cf9685a7418b4 ppc64le thunderbird-140.11.0-1.el8_10.ppc64le.rpm SHA-256: d44698e6ebe7494bd03de7e407ded3b1fa8a16310e420e009ea19e8631c68056 thunderbird-debuginfo-140.11.0-1.el8_10.ppc64le.rpm SHA-256: e003e76547225a2678d1f8d2ad398ce81ee389227ee873d474f3bb96dcecb2bd thunderbird-debugsource-140.11.0-1.el8_10.ppc64le.rpm SHA-256: 2e09bfde558e71693c53adf7ca33205c09ef9cda64d677ca7e16bfa0dd9e5541 Red Hat Enterprise Linux for ARM 64 8 SRPM thunderbird-140.11.0-1.el8_10.src.rpm SHA-256: b110738c866c4a864c3d2850dda33f224af3ac8a0c9dae5aa64cf9685a7418b4 aarch64 thunderbird-140.11.0-1.el8_10.aarch64.rpm SHA-256: 1c9bf4de34fb8fdddc0b3db3719c82a0585700474f363af892b12d3e97a63c00 thunderbird-debuginfo-140.11.0-1.el8_10.aarch64.rpm SHA-256: d5f0c2f1467056123752e9b3040b62931062ab5dd8a0bbaeb89f8c5e3d91cb24 thunderbird-debugsource-140.11.0-1.el8_10.aarch64.rpm SHA-256: 355682938230eea55d2edd7e6d61a547bcf7a4835c31ea863f5e603e4b2a79fc Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 8.10 SRPM thunderbird-140.11.0-1.el8_10.src.rpm SHA-256: b110738c866c4a864c3d2850dda33f224af3ac8a0c9dae5aa64cf9685a7418b4 x86_64 thunderbird-140.11.0-1.el8_10.x86_64.rpm SHA-256: 7a7b2d592387a48de2f1d994acb94f288df4fdb3d1abc0650fe9b8f68fe1a43a thunderbird-debuginfo-140.11.0-1.el8_10.x86_64.rpm SHA-256: 278f7dc73efddfca5af4de20a7deb9b5a11ce01725f5a22390e2e962e9e243c6 thunderbird-debugsource-140.11.0-1.el8_10.x86_64.rpm SHA-256: e9a19da76265d07d94f26008793020662d9c54d7594c9b3b7e7931310f20583d Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 8.10 SRPM thunderbird-140.11.0-1.el8_10.src.rpm SHA-256: b110738c866c4a864c3d2850dda33f224af3ac8a0c9dae5aa64cf9685a7418b4 aarch64 thunderbird-140.11.0-1.el8_10.aarch64.rpm SHA-256: 1c9bf4de34fb8fdddc0b3db3719c82a0585700474f363af892b12d3e97a63c00 thunderbird-debuginfo-140.11.0-1.el8_10.aarch64.rpm SHA-256: d5f0c2f1467056123752e9b3040b62931062ab5dd8a0bbaeb89f8c5e3d91cb24 thunderbird-debugsource-140.11.0-1.el8_10.aarch64.rpm SHA-256: 355682938230eea55d2edd7e6d61a547bcf7a4835c31ea863f5e603e4b2a79fc Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 8.10 SRPM thunderbird-140.11.0-1.el8_10.src.rpm SHA-256: b110738c866c4a864c3d2850dda33f224af3ac8a0c9dae5aa64cf9685a7418b4 ppc64le thunderbird-140.11.0-1.el8_10.ppc64le.rpm SHA-256: d44698e6ebe7494bd03de7e407ded3b1fa8a16310e420e009ea19e8631c68056 thunderbird-debuginfo-140.11.0-1.el8_10.ppc64le.rpm SHA-256: e003e76547225a2678d1f8d2ad398ce81ee389227ee873d474f3bb96dcecb2bd thunderbird-debugsource-140.11.0-1.el8_10.ppc64le.rpm SHA-256: 2e09bfde558e71693c53adf7ca33205c09ef9cda64d677ca7e16bfa0dd9e5541 Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 8.10 SRPM thunderbird-140.11.0-1.el8_10.src.rpm SHA-256: b110738c866c4a864c3d2850dda33f224af3ac8a0c9dae5aa64cf9685a7418b4 s390x thunderbird-140.11.0-1.el8_10.s390x.rpm SHA-256: 06498c31c4bf50b1747f107aaed58d3749cbad3b7dd62ed29145722c3999e8a7 thunderbird-debuginfo-140.11.0-1.el8_10.s39