Red Hat Product Errata RHSA-2026:27715 - Security Advisory Issued: 2026-06-22 Updated: 2026-06-22 RHSA-2026:27715 - 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 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 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 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 - 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 for x86_64 - Extended Update Support 10.0 SRPM firefox-140.11.0-1.el10_0.src.rpm SHA-256: 375f90d48ad93e4694100aa6eba0adf231d21ee86c92c866444f2f39a74229f7 x86_64 firefox-140.11.0-1.el10_0.x86_64.rpm SHA-256: 7c6cbc93b641964ce208fea9ae351a25b4fc7ac2a32409bc7f107e6ca9db9974 firefox-debuginfo-140.11.0-1.el10_0.x86_64.rpm SHA-256: 065fb20db31ea30801da57aefb71b74050a1cdc20581de1b705724e1ff9f1508 firefox-debugsource-140.11.0-1.el10_0.x86_64.rpm SHA-256: 02180258109ad93e59614afdffab591778d6b5f860cd5f7511dde74c06b5be3b Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.0 SRPM firefox-140.11.0-1.el10_0.src.rpm SHA-256: 375f90d48ad93e4694100aa6eba0adf231d21ee86c92c866444f2f39a74229f7 s390x firefox-140.11.0-1.el10_0.s390x.rpm SHA-256: 9169853969a101f7212811308a8a3d595653d1d2ecbc58ad90fd89cae04f0327 firefox-debuginfo-140.11.0-1.el10_0.s390x.rpm SHA-256: 27765d062576a0388d4d3460d34fd06fcd403d7db6dc273a104196b6e3a7fee5 firefox-debugsource-140.11.0-1.el10_0.s390x.rpm SHA-256: 174d3b7947c0babc9104b13982348aa356d31db0af9d5d306645ff6f077440f0 Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.0 SRPM firefox-140.11.0-1.el10_0.src.rpm SHA-256: 375f90d48ad93e4694100aa6eba0adf231d21ee86c92c866444f2f39a74229f7 ppc64le firefox-140.11.0-1.el10_0.ppc64le.rpm SHA-256: 9793473dfc30f6199acf70add4fd50e957174eaaa5f0a2b98b05c0e7f46e3ea6 firefox-debuginfo-140.11.0-1.el10_0.ppc64le.rpm SHA-256: 9783a29c0b16df05ec3024b4cc39de89ccbc5c717b4d7e305cb11e1fb2e9d4bd firefox-debugsource-140.11.0-1.el10_0.ppc64le.rpm SHA-256: 425b30f9add9209a63b61dae0fa2e0a974489969e340b78eab7edc1a1038551c Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.0 SRPM firefox-140.11.0-1.el10_0.src.rpm SHA-256: 375f90d48ad93e4694100aa6eba0adf231d21ee86c92c866444f2f39a74229f7 aarch64 firefox-140.11.0-1.el10_0.aarch64.rpm SHA-256: eebe874b2da35d004a51fb5cbae8bdbfef44d08fff4e7e900edb117e11f07931 firefox-debuginfo-140.11.0-1.el10_0.aarch64.rpm SHA-256: d6e111297c5c0dc91f77197da81c48cf11c594d2d0cec057010bb6c237a90a4b firefox-debugsource-140.11.0-1.el10_0.aarch64.rpm SHA-256: 38fd22c29e701dbe11378354a07dd9b961e89ca04876dfe2a18bf21df34d07bf Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.0 SRPM firefox-140.11.0-1.el10_0.src.rpm SHA-256: 375f90d48ad93e4694100aa6eba0adf231d21ee86c92c866444f2f39a74229f7 aarch64 firefox-140.11.0-1.el10_0.aarch64.rpm SHA-256: eebe874b2da35d004a51fb5cbae8bdbfef44d08fff4e7e900edb117e11f07931 firefox-debuginfo-140.11.0-1.el10_0.aarch64.rpm SHA-256: d6e111297c5c0dc91f77197da81c48cf11c594d2d0cec057010bb6c237a90a4b firefox-debugsource-140.11.0-1.el10_0.aarch64.rpm SHA-256: 38fd22c29e701dbe11378354a07dd9b961e89ca04876dfe2a18bf21df34d07bf Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 10.0 SRPM firefox-140.11.0-1.el10_0.src.rpm SHA-256: 375f90d48ad93e4694100aa6eba0adf231d21ee86c92c866444f2f39a74229f7 s390x firefox-140.11.0-1.el10_0.s390x.rpm SHA-256: 9169853969a101f7212811308a8a3d595653d1d2ecbc58ad90fd89cae04f0327 firefox-debuginfo-140.11.0-1.el10_0.s390x.rpm SHA-256: 27765d062576a0388d4d3460d34fd06fcd403d7db6dc273a104196b6e3a7fee5 firefox-debugsource-140.11.0-1.el10_0.s390x.rpm SHA-256: 174d3b7947c0babc9104b13982348aa356d31db0af9d5d306645ff6f077440f0 Red Hat Enterprise Linux for Power, little endian - 4 years of support 10.0 SRPM firefox-140.11.0-1.el10_0.src.rpm SHA-256: 375f90d48ad93e4694100aa6eba0adf231d21ee86c92c866444f2f39a74229f7 ppc64le firefox-140.11.0-1.el10_0.ppc64le.rpm SHA-256: 9793473dfc30f6199acf70add4fd50e957174eaaa5f0a2b98b05c0e7f46e3ea6 firefox-debuginfo-140.11.0-1.el10_0.ppc64le.rpm SHA-256: 9783a29c0b16df05ec3024b4cc39de89ccbc5c717b4d7e305cb11e1fb2e9d4bd firefox-debugsource-140.11.0-1.el10_0.ppc64le.rpm SHA-256: 425b30f9add9209a63b61dae0fa2e0a974489969e340b78eab7edc1a1038551c Red Hat Enterprise Linux for x86_64 - 4 years of updates 10.0 SRPM firefox-140.11.0-1.el10_0.src.rpm SHA-256: 375f90d48ad93e4694100aa6eba0adf231d21ee86c92c866444f2f39a74229f7 x86_64 firefox-140.11.0-1.el10_0.x86_64.rpm SHA-256: 7c6cbc93b641964ce208fea9ae351a25b4fc7ac2a32409bc7f107e6ca9db9974 firefox-debuginfo-140.11.0-1.el10_0.x86_64.rpm SHA-256: 065fb20db31ea30801da57aefb71b74050a1cdc20581de1b705724e1ff9f1508 firefox-