Mozilla security advisory (AV26-868)

Serial number: AV26-868
Date: September 1, 2026

As of September 1, 2026, Mozilla is affected by vulnerabilities in the following products:

• Firefox ESR
  • Versions prior to 115.40
  • Versions prior to 140.15
  • Versions prior to 153.2
• Firefox
  • Versions prior to 155

The Cyber Centre encourages users and administrators to review the provided web links and apply any necessary updates as they become available.

• Security Vulnerabilities fixed in Firefox ESR 115.40 — Mozilla
• Security Vulnerabilities fixed in Firefox ESR 140.15 — Mozilla
• Security Vulnerabilities fixed in Firefox ESR 153.2 — Mozilla
• Security Vulnerabilities fixed in Firefox 155 — Mozilla
• Mozilla Foundation Security Advisories — Mozilla