Improper access control in Mozilla products - CVE-2026-74942

Vulnerability identifier: #VU144049

CSH Severity: High

CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-74942

CWE-ID: CWE-284

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to escalate privileges.

The vulnerability exists due to improper access control in the Remote Settings Client component when processing remote settings data. A remote attacker can trigger crafted browser interactions to escalate privileges.

Mozilla Firefox
Firefox ESR
Firefox for Android
Debian Linux
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Micro for Rancher
SUSE Linux Enterprise Micro
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Anolis OS
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Desktop Applications Module
Basesystem Module
SUSE Package Hub 15
openSUSE Leap
openEuler
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
rust-cbindgen-debuginfo
rust-cbindgen
rust-cbindgen-debugsource
mozilla-nss-certs
mozilla-nss-certs-debuginfo
mozilla-nss-sysinit
libfreebl3
mozilla-nss-debugsource
mozilla-nss-devel
mozilla-nss-tools-debuginfo
mozilla-nss-tools
mozilla-nss-debuginfo
libfreebl3-32bit
libfreebl3-debuginfo-32bit
libsoftokn3-debuginfo
libfreebl3-debuginfo
mozilla-nss-sysinit-debuginfo-32bit
mozilla-nss-32bit
libsoftokn3-debuginfo-32bit
mozilla-nss-certs-debuginfo-32bit
mozilla-nss-certs-32bit
libsoftokn3-32bit
mozilla-nss-sysinit-debuginfo
mozilla-nss-debuginfo-32bit
mozilla-nss-sysinit-32bit
libsoftokn3
mozilla-nss
mozilla-nss-64bit
mozilla-nss-64bit-debuginfo
libfreebl3-64bit
libfreebl3-64bit-debuginfo
libsoftokn3-64bit-debuginfo
mozilla-nss-sysinit-64bit
mozilla-nss-certs-64bit
mozilla-nss-sysinit-64bit-debuginfo
mozilla-nss-certs-64bit-debuginfo
libsoftokn3-64bit
mozilla-nss-sysinit-32bit-debuginfo
mozilla-nss-32bit-debuginfo
libfreebl3-32bit-debuginfo
mozilla-nss-certs-32bit-debuginfo
libsoftokn3-32bit-debuginfo
mozilla-nspr-32bit
mozilla-nspr-devel
mozilla-nspr-debuginfo-32bit
mozilla-nspr-debugsource
mozilla-nspr
mozilla-nspr-debuginfo
mozilla-nspr-64bit-debuginfo
mozilla-nspr-32bit-debuginfo
mozilla-nspr-64bit
thunderbird (Debian package)
firefox-esr (Debian package)
firefox
thunderbird-wayland
firefox-debuginfo
firefox-debugsource
thunderbird-debuginfo
thunderbird-librnp-rnp
thunderbird-debugsource
thunderbird
firefox (Red Hat package)
thunderbird (Red Hat package)
MozillaFirefox-translations-common
MozillaFirefox
MozillaFirefox-devel
MozillaFirefox-debuginfo
MozillaFirefox-debugsource
MozillaThunderbird-debuginfo
MozillaThunderbird-translations-common
MozillaThunderbird-debugsource
MozillaThunderbird
MozillaThunderbird-translations-other
MozillaFirefox-translations-other
MozillaFirefox-branding-upstream
MozillaFirefox-branding-SLE
Mozilla Thunderbird

Install security update from vendor's website.

Mozilla Firefox - update to 154.0
Firefox for Android - update to 154.0
Firefox ESR - addressed in versions 115.39.0, 140.14.0, 153.1.0
Mozilla Thunderbird - addressed in versions 140.14.0, 153.1.0, 154.0
rust-cbindgen-debuginfo - update to 0.29.4+git0-150400.11.3.2
rust-cbindgen - update to 0.29.4+git0-150400.11.3.2
rust-cbindgen-debugsource - update to 0.29.4+git0-150400.11.3.2
mozilla-nss-certs - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-certs-debuginfo - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-sysinit - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libfreebl3 - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-debugsource - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-devel - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-tools-debuginfo - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-tools - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-debuginfo - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libfreebl3-32bit - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libfreebl3-debuginfo-32bit - update to 3.125-58.147.1
libsoftokn3-debuginfo - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libfreebl3-debuginfo - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-sysinit-debuginfo-32bit - update to 3.125-58.147.1
mozilla-nss-32bit - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libsoftokn3-debuginfo-32bit - update to 3.125-58.147.1
mozilla-nss-certs-debuginfo-32bit - update to 3.125-58.147.1
mozilla-nss-certs-32bit - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libsoftokn3-32bit - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-sysinit-debuginfo - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-debuginfo-32bit - update to 3.125-58.147.1
mozilla-nss-sysinit-32bit - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libsoftokn3 - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-64bit - update to 3.125-150400.3.74.1
mozilla-nss-64bit-debuginfo - update to 3.125-150400.3.74.1
libfreebl3-64bit - update to 3.125-150400.3.74.1
libfreebl3-64bit-debuginfo - update to 3.125-150400.3.74.1
libsoftokn3-64bit-debuginfo - update to 3.125-150400.3.74.1
mozilla-nss-sysinit-64bit - update to 3.125-150400.3.74.1
mozilla-nss-certs-64bit - update to 3.125-150400.3.74.1
mozilla-nss-sysinit-64bit-debuginfo - update to 3.125-150400.3.74.1
mozilla-nss-certs-64bit-debuginfo - update to 3.125-150400.3.74.1
libsoftokn3-64bit - update to 3.125-150400.3.74.1
mozilla-nss-sysinit-32bit-debuginfo - update to 3.125-150400.3.74.1
mozilla-nss-32bit-debuginfo - update to 3.125-150400.3.74.1
libfreebl3-32bit-debuginfo - update to 3.125-150400.3.74.1
mozilla-nss-certs-32bit-debuginfo - update to 3.125-150400.3.74.1
libsoftokn3-32bit-debuginfo - update to 3.125-150400.3.74.1
mozilla-nspr-32bit - addressed in versions 4.39-19.39.1, 4.39-150400.12.3.1
mozilla-nspr-devel - addressed in versions 4.39-19.39.1, 4.39-150400.12.3.1
mozilla-nspr-debuginfo-32bit - update to 4.39-19.39.1
mozilla-nspr-debugsource - addressed in versions 4.39-19.39.1, 4.39-150400.12.3.1
mozilla-nspr - addressed in versions 4.39-19.39.1, 4.39-150400.12.3.1
mozilla-nspr-debuginfo - addressed in versions 4.39-19.39.1, 4.39-150400.12.3.1
mozilla-nspr-64bit-debuginfo - update to 4.39-150400.12.3.1
mozilla-nspr-32bit-debuginfo - update to 4.39-150400.12.3.1
mozilla-nspr-64bit - update to 4.39-150400.12.3.1
thunderbird (Debian package) - update to 1:140.14.0esr-1~deb13u1
firefox-esr (Debian package) - update to 140.14.0esr-1~deb13u1
firefox - update to 140.14.0-1
thunderbird-wayland - update to 140.14.0-1
firefox-debuginfo - update to 140.14.0-1
firefox-debugsource - update to 140.14.0-1
thunderbird-debuginfo - update to 140.14.0-1
thunderbird-librnp-rnp - update to 140.14.0-1
thunderbird-debugsource - update to 140.14.0-1
thunderbird - update to 140.14.0-1
firefox (Red Hat package) - addressed in versions 140.14.0-1.el7_9, 140.14.0-1.el8_4, 140.14.0-1.el8_6, 140.14.0-1.el8_8, 140.14.0-1.el8_10, 140.14.0-1.el9_4, 140.14.0-1.el9_6, 140.14.0-1.el9_8, 140.14.0-1.el10_2
thunderbird (Red Hat package) - addressed in versions 140.14.0-1.el8_4, 140.14.0-1.el8_6, 140.14.0-1.el8_8, 140.14.0-1.el8_10, 140.14.0-1.el9_2, 140.14.0-1.el9_6, 140.14.0-1.el10_0, 140.14.0-1.el10_2
thunderbird - update to 140.14.0-1.0.1
firefox - update to 140.14.0-1.0.1
MozillaFirefox-translations-common - addressed in versions 140.14.0-112.327.1, 140.14.0-150200.152.251.1, 153.2.0-118.5.4, 153.2.0-150400.157.5.1
MozillaFirefox - addressed in versions 140.14.0-112.327.1, 140.14.0-150200.152.251.1, 153.2.0-118.5.4, 153.2.0-150400.157.5.1
MozillaFirefox-devel - addressed in versions 140.14.0-112.327.1, 140.14.0-150200.152.251.1, 153.2.0-118.5.4, 153.2.0-150400.157.5.1
MozillaFirefox-debuginfo - addressed in versions 140.14.0-112.327.1, 140.14.0-150200.152.251.1, 153.2.0-118.5.4, 153.2.0-150400.157.5.1
MozillaFirefox-debugsource - addressed in versions 140.14.0-112.327.1, 140.14.0-150200.152.251.1, 153.2.0-118.5.4, 153.2.0-150400.157.5.1
MozillaThunderbird-debuginfo - update to 140.14.0-150200.8.283.1
MozillaThunderbird-translations-common - update to 140.14.0-150200.8.283.1
MozillaThunderbird-debugsource - update to 140.14.0-150200.8.283.1
MozillaThunderbird - update to 140.14.0-150200.8.283.1
MozillaThunderbird-translations-other - update to 140.14.0-150200.8.283.1
MozillaFirefox-translations-other - addressed in versions 140.14.0-150200.152.251.1, 153.2.0-150400.157.5.1
MozillaFirefox-branding-upstream - update to 153.2.0-150400.157.5.1
MozillaFirefox-branding-SLE - addressed in versions 153-41.3.8, 153-150400.14.3.1

• https://www.mozilla.org/en-US/security/advisories/mfsa2026-75/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-77/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-76/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-74/
• https://bugzilla.mozilla.org/show_bug.cgi?id=2056571

• Multiple vulnerabilities in Mozilla Firefox and Firefox ESR
• Multiple vulnerabilities in Mozilla Thunderbird and Thunderbird ESR
• Multiple vulnerabilities in Mozilla Thunderbird ESR 153
• Multiple vulnerabilities in Mozilla Thunderbird
• Debian update for firefox-esr
• SUSE update for MozillaFirefox
• Debian update for thunderbird
• Red Hat Enterprise Linux 9 update for firefox
• Red Hat Enterprise Linux 8 update for firefox
• Red Hat Enterprise Linux 10 update for firefox
• SUSE update for MozillaFirefox
• openEuler 24.03 LTS SP4 update for thunderbird
• openEuler 24.03 LTS SP3 update for thunderbird
• openEuler 24.03 LTS SP4 update for firefox
• openEuler 24.03 LTS SP3 update for firefox
• openEuler 24.03 LTS SP1 update for firefox
• openEuler 22.03 LTS SP4 update for firefox
• SUSE update for MozillaThunderbird
• Anolis OS update for firefox
• Red Hat Enterprise Linux 8 update for firefox
• Red Hat Enterprise Linux 9 update for firefox
• Red Hat Enterprise Linux 8 update for firefox
• Red Hat Enterprise Linux 8 update for firefox
• Red Hat Enterprise Linux 9 update for firefox
• Red Hat Enterprise Linux 10 update for thunderbird
• Red Hat Enterprise Linux 8 update for thunderbird
• Red Hat Enterprise Linux 7 Extended Lifecycle Support update for firefox
• Red Hat Enterprise Linux 10 update for thunderbird
• Red Hat Enterprise Linux 9 update for thunderbird
• Red Hat Enterprise Linux 8 update for thunderbird
• Red Hat Enterprise Linux 8 update for thunderbird
• Red Hat Enterprise Linux 8 update for thunderbird
• Red Hat Enterprise Linux 9 update for thunderbird
• SUSE update for MozillaFirefox, MozillaFirefox-branding-SLE, mozilla-nspr, mozilla-nss, rust-cbindgen
• SUSE update for MozillaFirefox, mozilla-nspr, mozilla-nss, rust-cbindgen
• Anolis OS update for thunderbird