CVE-2026-84140
An attacker can exploit multiple vulnerabilities in Mozilla Firefox and Thunderbird to escalate privileges, bypass security measures, disclose sensitive information, manipulate data, conduct spoofing attacks, possibly execute arbitrary code through memory corruption, or cause Denial of Service conditions.
CSIRTS triage
- What
- Multiple vulnerabilities in Mozilla Firefox and Thunderbird enable privilege escalation, security bypass, information disclosure, memory corruption with potential arbitrary code execution, and Denial of Service.
- Who is affected
- All users of Firefox and Thunderbird across all versions.
- Urgency
- High severity with multiple attack vectors including potential code execution; immediate patching is critical.
- Action
- Update Firefox and Thunderbird to the latest available version.
AI-assisted analysis generated from the source advisory — verify against the original.
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Advisory coverage (4)
- high[NEW] [high] Mozilla Firefox and Thunderbird: Multiple Vulnerabilitiescert-bund · 2026-09-03
- unknownMozilla Products Multiple Vulnerabilitieshkcert · 2026-09-02
- unknownMultiple vulnerabilities in Mozilla products (02 September 2026)cert-fr-avis · 2026-09-02
- unknownCVE-2026-84140: Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox…nvd · 2026-09-01
External references
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