Summary
DOM Expressions has a Cross-Site Scripting (XSS) vulnerability due to improper use of string.replace
[!NOTE]
This advisory was originally emailed to [email protected] 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.
Impact
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2025-27108 has a CVSS score of 7.3 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.39.5); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-27108? CVE-2025-27108 is a high-severity cross-site scripting (XSS) vulnerability in dom-expressions (npm), affecting versions < 0.39.5. It is fixed in 0.39.5. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2025-27108? CVE-2025-27108 has a CVSS score of 7.3 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of dom-expressions are affected by CVE-2025-27108? dom-expressions (npm) versions < 0.39.5 is affected.
- Is there a fix for CVE-2025-27108? Yes. CVE-2025-27108 is fixed in 0.39.5. Upgrade to this version or later.
- Is CVE-2025-27108 exploitable, and should I be worried? Whether CVE-2025-27108 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-27108 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-27108? Upgrade
dom-expressionsto 0.39.5 or later.