The parent process would not properly check whether the Speech Synthesis feature is enabled, when receiving instructions from a child process. This vulnerability affects Thunderbird < 91.9.
[
{
"vendor": "Mozilla",
"product": "Thunderbird",
"versions": [
{
"version": "unspecified",
"lessThan": "91.9",
"status": "affected",
"versionType": "custom"
}
]
}
]