CVE-2026-4729
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk25th percentile - higher than 25% of all known CVEs
Summary
Memory safety bugs were found in Firefox 148 and Thunderbird 148. Some of these bugs showed evidence of memory corruption, which could potentially allow arbitrary code execution. The vulnerabilities were fixed in Firefox 149 and Thunderbird 149.
Risk Assessment
An attacker could exploit these vulnerabilities to execute arbitrary code remotely on the victim's system, leading to application takeover and potentially full system compromise.
Recommendation
Immediately update Firefox to version 149 and Thunderbird to version 149.
Original NVD description (English source)
Memory safety bugs present in Firefox 148 and Thunderbird 148. 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 149 and Thunderbird 149.