Inside the JavaScript parser, a cast of an integer to a narrower type can result in data read from outside the buffer being parsed. This usually results in a non-exploitable crash, but can leak a limited amount of information from memory if it matches JavaScript identifier syntax. This vulnerability affects Firefox < 56.
[
{
"product": "Firefox",
"vendor": "Mozilla",
"versions": [
{
"lessThan": "56",
"status": "affected",
"version": "unspecified",
"versionType": "custom"
}
]
}
]