CVE-2026-6766
firefox-esrVulnerabilityCVSS 7.5Patched
No public exploitation has been reported so far. A fixed version is available (see the table below).
Recommended action: Update to the fixed version listed for your distribution using the native package manager.
Severity metrics
CVSS 3.1 : 7.5 HIGH
Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
Confidentiality impactHigh
Integrity impactNone
Availability impactNone
Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
| Distribution | Package | Affected | Fixed version | Status |
|---|---|---|---|---|
| Debian:11 | firefox-esr | - | 140.10.0esr-1~deb11u1 | fixed |
| Debian:12 | firefox-esr | - | 140.10.0esr-1~deb12u1 | fixed |
| Debian:13 | firefox-esr | - | 140.10.0esr-1~deb13u1 | fixed |
| Debian:14 | firefox-esr | - | 140.10.0esr-1 | fixed |
| Debian:11 | thunderbird | - | 1:140.10.0esr-1~deb11u1 | fixed |
| Debian:12 | thunderbird | - | 1:140.10.0esr-1~deb12u1 | fixed |
| Debian:13 | thunderbird | - | 1:140.10.0esr-1~deb13u1 | fixed |
| Debian:14 | thunderbird | - | 1:140.10.0esr-1 | fixed |
| openSUSE:Tumbleweed | MozillaFirefox | - | 150.0-1.1 | fixed |
| openSUSE:Tumbleweed | MozillaThunderbird | - | 140.9.1-1.1 | fixed |
| openSUSE:Tumbleweed | firefox-esr | - | 153.0-1.1 | fixed |
| Red Hat:enterprise_linux:9::appstream | firefox | - | 0:140.10.0-1.el9_7 | fixed |
| Red Hat:enterprise_linux:8::appstream | firefox | - | 0:140.10.0-1.el8_10 | fixed |
| Red Hat:enterprise_linux:10.1 | firefox | - | 0:140.10.0-1.el10_1 | fixed |
| Red Hat:rhel_e4s:8.8::appstream | firefox | - | 0:140.10.0-1.el8_8 | fixed |
| Red Hat:rhel_tus:8.8::appstream | firefox | - | 0:140.10.0-1.el8_8 | fixed |
| Red Hat:rhel_e4s:9.0::appstream | firefox | - | 0:140.10.0-1.el9_0 | fixed |
| Red Hat:rhel_eus:9.6::appstream | firefox | - | 0:140.10.0-1.el9_6 | fixed |
| Red Hat:rhel_e4s:9.2::appstream | firefox | - | 0:140.10.0-1.el9_2 | fixed |
| Red Hat:enterprise_linux_eus:10.0 | firefox | - | 0:140.10.0-1.el10_0 | fixed |
| Red Hat:enterprise_linux:10.2 | firefox | - | 0:140.10.0-1.el10_2 | fixed |
| Red Hat:enterprise_linux:9::appstream | firefox | - | 0:140.10.0-1.el9_8 | fixed |
| Red Hat:rhel_eus:9.4::appstream | firefox | - | 0:140.10.0-1.el9_4 | fixed |
| Red Hat:rhel_aus:8.6::appstream | firefox | - | 0:140.10.0-1.el8_6 | fixed |
| Red Hat:rhel_e4s:8.6::appstream | firefox | - | 0:140.10.0-1.el8_6 | fixed |
| Red Hat:rhel_tus:8.6::appstream | firefox | - | 0:140.10.0-1.el8_6 | fixed |
| Red Hat:rhel_aus:8.4::appstream | firefox | - | 0:140.10.0-1.el8_4 | fixed |
| Red Hat:rhel_eus_long_life:8.4::appstream | firefox | - | 0:140.10.0-1.el8_4 | fixed |
| Red Hat:rhel_els:7 | firefox | - | 0:140.10.0-2.el7_9 | fixed |
| Red Hat:enterprise_linux:10.1 | thunderbird | - | 0:140.10.0-1.el10_1 | fixed |
| Red Hat:enterprise_linux:8::appstream | thunderbird | - | 0:140.10.0-1.el8_10 | fixed |
| Red Hat:enterprise_linux:9::appstream | thunderbird | - | 0:140.10.0-1.el9_7 | fixed |
| Red Hat:enterprise_linux:10.2 | thunderbird | - | 0:140.10.0-1.el10_2 | fixed |
| Red Hat:enterprise_linux:9::appstream | thunderbird | - | 0:140.10.1-1.el9_8 | fixed |
| Red Hat:rhel_e4s:9.2::appstream | thunderbird | - | 0:140.10.0-1.el9_2 | fixed |
| Red Hat:rhel_eus:9.6::appstream | thunderbird | - | 0:140.10.0-1.el9_6 | fixed |
| Red Hat:enterprise_linux_eus:10.0 | thunderbird | - | 0:140.10.0-1.el10_0 | fixed |
| Red Hat:rhel_aus:8.4::appstream | thunderbird | - | 0:140.10.0-1.el8_4 | fixed |
| Red Hat:rhel_eus_long_life:8.4::appstream | thunderbird | - | 0:140.10.0-1.el8_4 | fixed |
| Red Hat:rhel_aus:8.6::appstream | thunderbird | - | 0:140.10.0-1.el8_6 | fixed |
| Red Hat:rhel_e4s:8.6::appstream | thunderbird | - | 0:140.10.0-1.el8_6 | fixed |
| Red Hat:rhel_tus:8.6::appstream | thunderbird | - | 0:140.10.0-1.el8_6 | fixed |
| Red Hat:rhel_e4s:8.8::appstream | thunderbird | - | 0:140.10.0-1.el8_8 | fixed |
| Red Hat:rhel_tus:8.8::appstream | thunderbird | - | 0:140.10.0-1.el8_8 | fixed |
| Red Hat:rhel_e4s:9.0::appstream | thunderbird | - | 0:140.10.0-1.el9_0 | fixed |
| Red Hat:rhel_eus:9.4::appstream | thunderbird | - | 0:140.10.0-1.el9_4 | fixed |