CVE-2026-74987
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk8th percentile - higher than 8% of all known CVEs
Summary
Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153 showed evidence of memory corruption or another security-relevant defect. We presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Risk Assessment
The bugs could lead to remote code execution or application crashes, potentially exposing users to attacks.
Recommendation
Update Thunderbird to version 154, 140.14, or 153.1 (or later) and Firefox to version 154, 140.14, or 153.1 to receive security fixes.
Original NVD description (English source)
Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.