Security Alert (A26-09-03): Multiple Vulnerabilities in FireFox

Description:

Mozilla has published the advisories (MFSA2026-82, MFSA2026-83, MFSA2026-84 and MFSA2026-85) to address multiple vulnerabilities in Firefox. A remote attacker could entice a user to open a web page with specially crafted content on a vulnerable browser to exploit the vulnerabilities.

Affected Systems:

• Firefox Windows versions prior to version 155
• Firefox ESR Windows versions prior to version 115.40, 140.15, 153.2

Impact:

Successful exploitation of the vulnerabilities could lead to remote code execution, denial of service, elevation of privilege, information disclosure, security restriction bypass or spoofing on an affected system.

Recommendation:

Mozilla has released new versions of the product to address the issues and they can be downloaded at the following URLs:
Firefox 155 (Windows)
https://www.mozilla.org/en-US/firefox/all/#product-desktop-release
Firefox ESR 115.40, 140.15, 153.2 (Windows)
https://www.mozilla.org/en-US/firefox/all/#product-desktop-esr

Users of affected systems should follow the recommendations provided by the vendor and take immediate actions to mitigate the risk.

More Information:

• https://www.mozilla.org/en-US/security/advisories/mfsa2026-82/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-83/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-84/
• https://www.mozilla.org/en-US/security/advisories/mfsa2026-85/
• https://www.hkcert.org/security-bulletin/mozilla-products-multiple-vulnerabilities_20260902
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-16365
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-16371
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-74952
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-75874
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-84117 (to CVE-2026-84145)