A malicious extension with the ‘search’ permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication. This vulnerability affects Firefox < 87.
[
{
"product": "Firefox",
"vendor": "Mozilla",
"versions": [
{
"lessThan": "87",
"status": "affected",
"version": "unspecified",
"versionType": "custom"
}
]
}
]