Red Hat alert RHSA-2026:21381-01 (thunderbird) [LWN.net]

An update for thunderbird is now available for Red Hat Enterprise Linux 9. 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. 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. This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.

Original: https://access.redhat.com/security/data/csaf/v2/advisories/2026/rhsa-2026_21381.json