A lack of in app notification for entering fullscreen mode could have lead to a malicious website spoofing browser chrome.<br>*This bug onl…

published 2023-06-02 3 y ago modified 2026-10-24 16 d ago also EUVD-2023-29650

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 51%
public exploits: 0; none known

A lack of in app notification for entering fullscreen mode could have lead to a malicious website spoofing browser chrome.<br>*This bug only affects Firefox Focus. Other versions of Firefox are unaffected.*. This vulnerability affects Firefox < 110 and Firefox ESR < 102.8.

Patch / fix

fixed in 2 distros 5

Mozilla Firefox 110
Mozilla Firefox ESR 102.8

red hat suse opensuse almalinux rocky linux

thunderbird RHEL 9 102.8.0-2.el9_1
thunderbird RHEL 8 102.8.0-2.el8_7
thunderbird RHEL 7 102.8.0-2.el7_9
firefox RHEL 8 102.8.0-2.el8_7
firefox RHEL 9 102.8.0-2.el9_1
firefox-x11 RHEL 9 102.8.0-2.el9_1
firefox RHEL 7 102.8.0-2.el7_9
thunderbird RHEL 8.2 TUS, RHEL 8.2 E4S, RHEL 8.2 AUS 102.8.0-2.el8_2

red hat advisories RHSA-2023:0824 RHSA-2023:0821 RHSA-2023:0819 RHSA-2023:0823 RHSA-2023:0817 RHSA-2023:0818

MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES 12 SP5 +6 more 102.8.0-112.150.1
MozillaFirefox SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 102.8.0-150200.152.78.1
MozillaFirefox SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE High Performance Computing 15 SP1-LTSS 102.8.0-150000.150.76.1

suse advisories SUSE-SU-2023:0469-1 SUSE-SU-2023:0466-1 SUSE-SU-2023:0461-1

firefox-esr openSUSE Tumbleweed 128.5.1-1.1
MozillaFirefox openSUSE Tumbleweed 110.0.1-1.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:12753-1

firefox AlmaLinux 8 102.8.0-2.el8_7.alma
firefox AlmaLinux 9 102.8.0-2.el9_1.alma
firefox-x11 AlmaLinux 9 102.8.0-2.el9_1.alma
thunderbird AlmaLinux 8 102.8.0-2.el8_7.alma
thunderbird AlmaLinux 9 102.8.0-2.el9_1.alma

almalinux advisories ALSA-2023:0808 ALSA-2023:0810 ALSA-2023:0821 ALSA-2023:0824

firefox Rocky Linux 9 102.8.0-2.el9_1
thunderbird Rocky Linux 9 102.8.0-2.el9_1
firefox Rocky Linux 8 102.8.0-2.el8_7
thunderbird Rocky Linux 8 102.8.0-2.el8_7

rocky linux advisories RLSA-2023:0810 RLSA-2023:0824 RLSA-2023:0808 RLSA-2023:0821

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-25743 updated 2026-11-07 cvss 7.5

Mozilla: Fullscreen notification not shown in Firefox Focus

Red Hat Enterprise Linux 6 firefox, thunderbird
affected: no fix planned “Out of support scope”
Red Hat Enterprise Linux AppStream (v. 8) firefox 102.8.0-2.el8_7, thunderbird 102.8.0-2.el8_7
fixed: vendor fix RHSA-2023:0808
Red Hat Enterprise Linux AppStream (v. 9) firefox 102.8.0-2.el9_1, firefox-x11 102.8.0-2.el9_1, thunderbird 102.8.0-2.el9_1
fixed: vendor fix RHSA-2023:0810
Red Hat Enterprise Linux AppStream AUS (v. 8.2) firefox 102.8.0-2.el8_2, thunderbird 102.8.0-2.el8_2
fixed: vendor fix RHSA-2023:0811
Red Hat Enterprise Linux AppStream E4S (v. 8.1) firefox 102.8.0-2.el8_1, thunderbird 102.8.0-2.el8_1
fixed: vendor fix RHSA-2023:0806
Red Hat Enterprise Linux AppStream E4S (v. 8.2) firefox 102.8.0-2.el8_2, thunderbird 102.8.0-2.el8_2
fixed: vendor fix RHSA-2023:0811
Red Hat Enterprise Linux AppStream EUS (v.8.4) firefox 102.8.0-2.el8_4, thunderbird 102.8.0-2.el8_4
fixed: vendor fix RHSA-2023:0805
Red Hat Enterprise Linux AppStream EUS (v.8.6) firefox 102.8.0-2.el8_6, thunderbird 102.8.0-2.el8_6
fixed: vendor fix RHSA-2023:0807

show 3 more

Red Hat Enterprise Linux AppStream EUS (v.9.0) firefox 102.8.0-2.el9_0, thunderbird 102.8.0-2.el9_0
fixed: vendor fix RHSA-2023:0809
Red Hat Enterprise Linux AppStream TUS (v. 8.2) firefox 102.8.0-2.el8_2, thunderbird 102.8.0-2.el8_2
fixed: vendor fix RHSA-2023:0811
Red Hat Enterprise Linux Client (v. 7) firefox 102.8.0-2.el7_9, thunderbird 102.8.0-2.el7_9 Red Hat Enterprise Linux Client Optional (v. 7) firefox 102.8.0-2.el7_9 Red Hat Enterprise Linux Server (v. 7) firefox 102.8.0-2.el7_9 Red Hat Enterprise Linux Server Optional (v. 7) firefox 102.8.0-2.el7_9, thunderbird 102.8.0-2.el7_9 Red Hat Enterprise Linux Workstation (v. 7) firefox 102.8.0-2.el7_9, thunderbird 102.8.0-2.el7_9 Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 102.8.0-2.el7_9
fixed: vendor fix RHSA-2023:0812

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: partial
Assessed: 21 mo ago (2025-01-09)

Exploit prediction

0.65% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

Mozilla Firefox
Mozilla Firefox ESR

Classification

Weakness

CWE-290 Authentication Bypass by Spoofing

References

mozilla.org /security/advisories/mfsa2023-06/
vendor-advisory
mozilla.org /security/advisories/mfsa2023-05/
vendor-advisory
bugzilla.mozilla.org /show_bug.cgi?id=1800203
issue-tracking, permissions-required

Sources

CVE List CVE-2023-25743
NVD CVE-2023-25743

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary