DOM Expressions has a Cross-Site Scripting (XSS) vulnerability due to improper use of string.replace
Date: 2025-02
Affected: npm/dom-expressions
Attack vector: xss
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2025-27108
CWE: CWE-116
CWE-79
CVSS: 7.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L)

> [!NOTE] > This advisory was originally emailed to community@solidjs.com by @nsysean. To sum it up, the use of javascript's `.replace()` opens up to potential XSS vulnerabilities with the special replacement patterns beginning with `$`. Particularly, when the attributes of `Meta` tag from solid-meta are user-defined, attackers can utilise the special replacement patterns, either `$'` or `$\`` to achieve XSS. The solid-meta package has this issue since it uses `useAffect` and context providers, which injects the used assets in the html header. "dom-expressions" uses `.replace()` to insert the assets, which is vulnerable to the special replacement patterns listed above. This effectively means that if the attributes of an asset tag contained user-controlled data, it would be vulnerable to XSS. For instance, there might be meta tags for the open graph protocol in a user profile page, but if attackers set the user query to some payload abusing `.replace()`, then they could execute arbitrary javascript in the victim's web browser. Moreover, it could be stored and cause more problems.


Mitigations:

Architectural layers (MAESTRO):