Crass: Incorrect tokenization of bad URLs enables CSS sanitizer bypass
概要
Crass is a Ruby CSS parser that is compliant with the CSS Syntax Level 3 specification. Prior to 1.0.8, Crass incorrectly treats a closing parenthesis after an escaped backslash as escaped while consuming the remnants of a bad URL. Crass therefore keeps declarations, style rules, or at-rules inside...
影響パッケージ
| 種類 | パッケージ | 影響を受ける版 | 直った版 |
|---|---|---|---|
| rgrove | crass | — | — |
原文の説明 取得元が公開している説明をそのまま載せています (多くは英語)。
Crass is a Ruby CSS parser that is compliant with the CSS Syntax Level 3 specification. Prior to 1.0.8, Crass incorrectly treats a closing parenthesis after an escaped backslash as escaped while consuming the remnants of a bad URL. Crass therefore keeps declarations, style rules, or at-rules inside a bad URL token even though a browser treats them as live CSS. A sanitizer that parses untrusted CSS with Crass and reserializes it without rejecting the bad URL can allow CSS used for UI redress, external resource loading, or CSS-based data exfiltration, but this issue does not enable script execution in modern browsers. This issue is fixed in version 1.0.8.
出典: CVE.org (CVE Program・cvelistV5) NVD