CVE-2025-27108 is a high-severity (CVSS 7.3) Cross-site Scripting (XSS) vulnerability in dom-expressions. O3 Security confirms whether CVE-2025-27108 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Cross-site Scripting vulnerability due to improper use of string.replace in dom-expressions
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
dom-expressionsnpmDescription
dom-expressions is a Fine-Grained Runtime for Performant DOM Rendering. In affected versions the use of javascript's .replace() opens up to potential Cross-site Scripting (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 useAffectand 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. This issue has been addressed in version 0.39.5 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | dom-expressions | all versions | 0.39.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dom-expressions. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update dom-expressions to 0.39.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-27108 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-27108 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-27108. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-27108 in your dependencies?
O3 detects CVE-2025-27108 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.