Opera 7.54 and earlier does not properly validate base64 encoded binary data in a data: (RFC 2397) URL, which causes the URL to be obscured in a download dialog, which may allow remote attackers to trick users into executing arbitrary code.
From 神龙GPT (AIGC)
Opera 7.54 和更早版本未正确验证数据：(RFC 2397)URL中的 base64 编码二进制数据，这导致下载对话框中隐藏了 URL，这可能导致远程攻击者欺骗用户执行任意代码。