CVE-2025-27793 — vega
Fix: vega/vega@694560cCVE-2025-27793 is a Cross-site Scripting (XSS) vulnerability in vega. A fix is available for vega — see the affected versions and patch details below.
Vega vulnerable to Cross-site Scripting via RegExp.prototype[@@replace]
Exploitation Status
No confirmed exploitation observed yet
- 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-2025-27793.
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.
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.
veganpmvega-functionsnpmDescription
Impact
Users running Vega/Vega-lite JSON definitions could run unexpected JavaScript code when drawing graphs, unless the library is used with the vega-interpreter.
Workarounds
- Use
vegawith expression interpreter - Upgrade to a newer Vega version (
5.32.0)
POC Summary
Calling replace with a RegExp-like pattern calls RegExp.prototype[@@replace], which can then call an attacker-controlled exec function.
POC Details
Consider the function call replace('foo', {__proto__: /h/.constructor.prototype, global: false}). Since pattern has RegExp.prototype[@@replace], pattern.exec('foo') winds up being called.
The resulting malicious call looks like this:
replace(<string argument>, {__proto__: /h/.constructor.prototype, exec: <function>, global: false})
Since functions cannot be returned from this, an attacker that wishes to escalate to XSS must abuse event.view to gain access to eval.
Reproduction steps
{"$schema":"https://vega.github.io/schema/vega/v5.json","signals":[{"name":"a","on":[{"events":"body:mousemove{99999}","update":"replace('alert(1)',{__proto__:/h/.constructor.prototype,exec:event.view.eval,global:false})"}]}]}
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | vega | all versions | 5.32.0npm install vega@5.32.0 |
| 📦npm | vega-functions | all versions | 5.17.0npm install vega-functions@5.17.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vega, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update vega to 5.32.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-27793 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-2025-27793 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-27793. 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-2025-27793 in your dependencies?
O3 Security finds CVE-2025-27793 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.