CVE-2026-16390
A security flaw in the Enterprise Policies component allows attackers to bypass existing security restrictions. This flaw can be exploited remotely without requiring user interaction.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Users of Firefox (versions prior to 153 or ESR 140.13) and Thunderbird (versions prior to 153 or 140.13) that utilize the Enterprise Policies component.
Real-world impact
An attacker could bypass organizational security policies, potentially allowing them to change browser settings or bypass restrictions intended to secure the application.
Why this severity
This is a critical vulnerability because it can be exploited over the network without any user interaction or special privileges, and it allows for high levels of data confidentiality and integrity loss.
What to do about it
- 011. Upgrade Firefox to version 153 or later.
- 022. Upgrade Firefox ESR to version 140.13 or later.
- 033. Upgrade Thunderbird to version 153 or later.
- 044. Upgrade Thunderbird to version 140.13 or later.
NVD-referenced vendor advisory
Timeline
- Jul 21, 2026 · 12d agoPublishedDisclosed and added to the National Vulnerability Database.
- Jul 22, 2026 · 10d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.
- Jul 24, 2026 · 9d agoAdvisory updatedThe NVD record was last revised.
How it’s attacked
References & advisories
- bugzilla.mozilla.org/show_bug.cgipermissions required
- mozilla.org/security/advisories/mfsa202…vendor advisory
- mozilla.org/security/advisories/mfsa202…vendor advisory
- mozilla.org/security/advisories/mfsa202…vendor advisory
- mozilla.org/security/advisories/mfsa202…vendor advisory