CVE-2026-16411: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 0.5% chance of exploitation in the next 30 days.

Memory safety bugs present in Firefox 152. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

Affected products

• Mozilla Firefox: before 153.0.0 (fixed in 153.0.0)

Published 2026-07-21. Last modified 2026-07-24.