Vulnerability in Mozilla Firefox

[ Why it matters ]Priority signals

• Critical severity: CVSS 9.8

[ Description ]Official description

Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 157.0.1 and Thunderbird 158.

[ Fixes ]Fixes and patches

• Security bulletin: Mozilla mfsa2026-104Vendor patch or bulletin · CERT-FR · mozilla.org/en-US/security/advisories/mfsa2026-104, cited by CERT-FR CERTFR-2026-AVI-1272

[ Advisories ]Government CERT advisories

• CERT-FR14 Oct 2026CERTFR-2026-AVI-1305

  Multiple vulnerabilities in Mozilla products Translated from French

  Multiple vulnerabilities have been discovered in Mozilla products. Some of them allow an attacker to cause privilege escalation, remote denial of service and a breach of data confidentiality.

  CVE-2026-109779CVE-2026-109710CVE-2026-109719+79 more CVEs
• CERT-FR7 Oct 2026CERTFR-2026-AVI-1272

  Vulnerability in Mozilla products Translated from French

  A vulnerability has been discovered in Mozilla products. It allows an attacker to cause a security policy bypass.

  CVE-2026-106016
• BSI CERT-Bund6 Oct 2026WID-SEC-2026-3788

  Mozilla Firefox: Vulnerability allows bypassing security measures Translated from German

  CVE-2026-106016

[ References ]References

• bugzilla.mozilla.org/show_bug.cgiPermissions Required
• www.mozilla.org/security/advisories/mfsa2026-104Vendor Advisory
• www.mozilla.org/security/advisories/mfsa2026-109