Security Advisory
CVE-2026-84142
9.8
CRITICAL
Vulnerability Description
Internally found bugs present in Thunderbird 154. 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 155 and Thunderbird 155.
Published Date
September 1, 2026
Official Source
NIST NVD Advisory