CVE-2025-27108 is a high-severity (CVSS 7.3) Cross-site Scripting (XSS) vulnerability in dom-expressions. A fix is available for dom-expressions — see the affected versions and patch details below.
Cross-site Scripting vulnerability due to improper use of string.replace in dom-expressions
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-27108.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-27108 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
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 | 0.39.5npm install dom-expressions@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-27108 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2025-27108 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.