It was possible to cause the use of a MessagePort after it had already been freed, which could potentially have led to an exploitable crash. This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.
120120115.5.0115.5.0Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:NI:NA:H6.5/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H