Red Hat Product Errata RHSA-2026:26551 - Security Advisory Issued: 2026-06-17 Updated: 2026-06-17 RHSA-2026:26551 - 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 7 Extended Lifecycle 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 Firefox is an open-source web browser, designed for standards compliance, performance, and portability. 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: 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 Server - Extended Life Cycle Support 7 x86_64 Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 s390x Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 ppc64 Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 ppc64le 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 - 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-2026-8961 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 Server - Extended Life Cycle Support 7 SRPM firefox-140.11.0-1.el7_9.src.rpm SHA-256: 8570d30506145b211a5a98f48753867b1992701c5f16f2a5bef2203bbb74db3b x86_64 firefox-140.11.0-1.el7_9.x86_64.rpm SHA-256: a2d5ac63592a815572f0189cef2b17a80b244acc963581f8e183fbcf38a46e03 Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 SRPM firefox-140.11.0-1.el7_9.src.rpm SHA-256: 8570d30506145b211a5a98f48753867b1992701c5f16f2a5bef2203bbb74db3b s390x firefox-140.11.0-1.el7_9.s390x.rpm SHA-256: 9f9c32873fc0f177108c44b2409e179b7fc907ea9e65480fee181971aa11c135 firefox-debuginfo-140.11.0-1.el7_9.s390x.rpm SHA-256: 6b6cff2e6e5ccc3feecd5c67c9ca1272c4d9375557cba259f01a347ff8bdb593 Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 SRPM firefox-140.11.0-1.el7_9.src.rpm SHA-256: 8570d30506145b211a5a98f48753867b1992701c5f16f2a5bef2203bbb74db3b ppc64 firefox-140.11.0-1.el7_9.ppc64.rpm SHA-256: e051c91973ef9645e1d58321cb3389b6aedc8a4636f5d81e4032df459b837e0a firefox-debuginfo-140.11.0-1.el7_9.ppc64.rpm SHA-256: 79a8240fd98253d5f81d41f455e365d4a915e41167e2f93152eb9d79c0428b58 Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 SRPM firefox-140.11.0-1.el7_9.src.rpm SHA-256: 8570d30506145b211a5a98f48753867b1992701c5f16f2a5bef2203bbb74db3b ppc64le firefox-140.11.0-1.el7_9.ppc64le.rpm SHA-256: 8a9e95f829d44f0396fd0820d02333ac4e5a5cfbca0367dfac4f0ac1190abcb9 firefox-debuginfo-140.11.0-1.el7_9.ppc64le.rpm SHA-256: 644eee397cb0f615956e625f610770cda7540ff1164312f92f235f38294001dc The Red Hat security contact is secalert@redhat.com . More contact details at https://access.redhat.com/security/team/contact/ .