Security Alert (A26-08-30): Multiple Vulnerabilities in FireFox


 

Published on: 19 August 2026

Description:

Mozilla has published the advisories (MFSA2026-74, MFSA2026-75, MFSA2026-76 and MFSA2026-77) 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 154
  • Firefox ESR Windows versions prior to version 115.39, 140.14, 153.1

 

Impact:

Successful exploitation of the vulnerabilities could lead to 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 154 (Windows)
https://www.mozilla.org/en-US/firefox/all/#product-desktop-release
Firefox ESR 115.39, 140.14, 153.1 (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/mfsa2026-74/
  • https://www.mozilla.org/en-US/security/advisories/mfsa2026-75/
  • https://www.mozilla.org/en-US/security/advisories/mfsa2026-76/
  • https://www.mozilla.org/en-US/security/advisories/mfsa2026-77/
  • https://www.hkcert.org/security-bulletin/mozilla-products-multiple-vulnerabilities_20260819
  • https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-74934 (to CVE-2026-74990)
  • https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-75874


Tag: Firefox , Mozilla
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