What is CVE-2023-25743?

CVE-2023-25743 is a high-severity vulnerability in Mozilla Firefox, classified under Authentication Bypass by Spoofing. CVSS score: 7.5/10. Published 2023-06-02.

How severe is CVE-2023-25743?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Mozilla Firefox

CVE-2023-25743

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.

Published 2023-06-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.006 (49.2th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Mozilla Firefox — versions unspecified
Mozilla Firefox Esr — versions unspecified
Mozilla Firefox Focus

Weakness classification (CWE)

CWE-290 — Authentication Bypass by Spoofing

References

www.mozilla.org/security/advisories/mfsa2023-06/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2023-05/ (Vendor Advisory)
bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)

Frequently asked questions

What is CVE-2023-25743?: CVE-2023-25743 is a high-severity vulnerability in Mozilla Firefox, classified under Authentication Bypass by Spoofing. CVSS score: 7.5/10. Published 2023-06-02.
How severe is CVE-2023-25743?: High severity. CVSS v3 base score is 7.5 out of 10.