medium
advisory
Mozilla Firefox, Firefox ESR, and Thunderbird vulnerabilities
Multiple vulnerabilities affecting Mozilla Firefox, Firefox ESR, and Thunderbird have been disclosed, necessitating updates to the latest versions to mitigate potential security risks.
Triage facts
Revision 1- Applicability
- Firefox (< 159), Firefox ESR (< 115.44) +3
- Evidence
- Unknown
- Severity
- Medium
- Action
- Elevated
- Sources
- 6 public sources
- Freshness
- Revision 1Oct 28, 23:59 UTC
- Source quality
- A1Likely
The Canadian Centre for Cyber Security (CCCS) has issued an advisory (AV26-1100) regarding security vulnerabilities identified in Mozilla Firefox, Firefox ESR, and Thunderbird. Users and administrators are advised to update their software to the versions specified in the Mozilla Foundation Security Advisories (MFSA2026-118, 119, 120, 121, and 122).
Recommendation
- Upgrade Firefox to version 159 or later.
- Upgrade Firefox ESR to version 115.44 or 153.6 or later.
- Upgrade Thunderbird to version 159 or 153.6 or later.
- Review the specific Mozilla Foundation Security Advisories linked in the references to understand the scope and impact of the patched vulnerabilities.
Mitigations
Update Firefox, Firefox ESR, and Thunderbird to the latest patched versions as identified in the advisory.
immediate
IT Operations
Vulnerabilities addressed in MFSA2026-118 through MFSA2026-122