Mozilla security advisory (AV26-976)
Canada's Cyber Centre urges updates for Firefox before 157 and three Firefox ESR branches after Mozilla security fixes.
On September 29, 2026, the Canadian Centre for Cyber Security issued advisory AV26-976 warning that Mozilla products are affected by security vulnerabilities. Listed builds are Firefox versions before 157 and Firefox ESR versions before 153.4, 140.17, and 115.42. The centre urges users and administrators to review Mozilla's advisories and apply available updates. The bulletin does not name CVE identifiers or say the flaws are being exploited.
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