A website could have obscured the fullscreen notification by using a URL with a scheme handled by an external program, such as a mailto URL. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 115, Firefox ESR < 102.13, and Thunderbird < 102.13.

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-37207
• https://bugzilla.mozilla.org/show_bug.cgi?id=1816287
• https://lists.debian.org/debian-lts-announce/2023/07/msg00006.html
• https://www.debian.org/security/2023/dsa-5450
• https://www.debian.org/security/2023/dsa-5451
• https://lists.debian.org/debian-lts-announce/2023/07/msg00015.html
• https://www.mozilla.org/security/advisories/mfsa2023-22
• https://www.mozilla.org/security/advisories/mfsa2023-23
• https://www.mozilla.org/security/advisories/mfsa2023-24