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 vulnerability was fixed in Firefox 149 and Thunderbird 149.
Risk Assessment
An attacker could exploit this vulnerability to execute arbitrary code on the victim's system, leading to full compromise of data confidentiality, integrity, and availability.
Recommendation
Immediately update Firefox to version 149 or later and Thunderbird to version 149 or later.
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.