Protection mechanism failure in Mozilla products - CVE-2026-74983

Vulnerability identifier: #VU144074

CSH Severity: Medium

CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-74983

CWE-ID: CWE-693

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to bypass a security mitigation.

The vulnerability exists due to improper protection mechanism implementation in the Data Loss Prevention component when processing web content. A remote attacker can trigger specially crafted web content to bypass a security mitigation.

User interaction is required to visit a specially crafted website or URL.

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

Install security update from vendor's website.

Firefox ESR - addressed in versions 140.14.0, 153.1.0
Firefox for Android - update to 154.0
Mozilla Firefox - update to 154.0
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-tools - 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
libsoftokn3-32bit - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-certs-32bit - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-certs-debuginfo-32bit - update to 3.125-58.147.1
libfreebl3-debuginfo-32bit - update to 3.125-58.147.1
libsoftokn3 - 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
mozilla-nss - 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
libfreebl3-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-debugsource - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-sysinit-32bit - 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-certs-debuginfo - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
mozilla-nss-certs - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libsoftokn3-debuginfo - 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-tools-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
mozilla-nss-debuginfo - addressed in versions 3.125-58.147.1, 3.125-150400.3.74.1
libsoftokn3-32bit-debuginfo - update to 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
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-devel - 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-32bit - 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-64bit - update to 4.39-150400.12.3.1
mozilla-nspr-32bit-debuginfo - update to 4.39-150400.12.3.1
firefox-esr (Debian package) - update to 140.14.0esr-1~deb13u1
thunderbird (Debian package) - update to 1:140.14.0esr-1~deb13u1
firefox-debugsource - update to 140.14.0-1
thunderbird - update to 140.14.0-1
firefox-debuginfo - update to 140.14.0-1
firefox - update to 140.14.0-1
thunderbird-wayland - update to 140.14.0-1
thunderbird-librnp-rnp - update to 140.14.0-1
thunderbird-debugsource - update to 140.14.0-1
thunderbird-debuginfo - 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
firefox - update to 140.14.0-1.0.1
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 - 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
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
MozillaThunderbird-translations-other - update to 140.14.0-150200.8.283.1
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
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/mfsa2026-76/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-77/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-74/
• https://bugzilla.mozilla.org/show_bug.cgi?id=2051897

• 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 7 Extended Lifecycle Support update for firefox
• SUSE update for MozillaFirefox, MozillaFirefox-branding-SLE, mozilla-nspr, mozilla-nss, rust-cbindgen
• SUSE update for MozillaFirefox, mozilla-nspr, mozilla-nss, rust-cbindgen