{"id":"GHSA-9h5v-pfqq-x599","summary":"UAParser.js: Unbounded `Sec-CH-UA-Model` parsing can trigger ReDoS in `withClientHints()`","details":"### Summary\n\nA regular expression denial-of-service (ReDoS) vulnerability has been discovered in `ua-parser-js` when using the Client Hints API. By sending a crafted `Sec-CH-UA-Model` header to an application that calls `UAParser(headers).withClientHints()`, an attacker can cause the parser to spend excessive CPU time due to catastrophic backtracking in the device [regex](https://github.com/faisalman/ua-parser-js/blob/2.0.9/src/main/ua-parser.js#L615):\n\n```js\n/ ([\\w ]+) miui\\/v?\\d/i\n```\n\nUnlike when using the `User-Agent` value, which has a hard limit of `UA_MAX_LENGTH = 500`, when using Client Hints, values are copied without a length limit before being passed into regex parsing.\n\n### PoC\n\n```js\nconst { UAParser } = require('ua-parser-js');\n\nconst headers = {\n  'sec-ch-ua-platform': '\"Android\"',\n  'sec-ch-ua-mobile': '?1',\n  'sec-ch-ua-model': '\"' + 'A '.repeat(25000) + '\"'\n};\n\nconst t0 = process.hrtime.bigint();\nUAParser(headers).withClientHints();\nconst ms = Number(process.hrtime.bigint() - t0) / 1e6;\n\nif (ms \u003e 100) {\n  console.log('Potential ReDoS');\n}\n```\n\n### Impact\n\nThis vulnerability allows an unauthenticated attacker to trigger a denial-of-service condition in any __server-side__ application that uses `UAParser(headers).withClientHints()`. A single request with a ~32,000-character model value can consume over 400ms of CPU time, with parsing time growing polynomially with input length. The impact is __availability__ only, there is no confidentiality or integrity impact.\n\n### Affected Versions\n\n`ua-parser-js` versions `\u003e=2.0.1, \u003c=2.0.9` are affected. The `withClientHints()` API is not present in version `0.7.x` or `1.x`.\n\n### Patches\n\nA patch has been released to fix the vulnerable regular expression and limit the Client Hints input. Users should update to version `2.0.10` or later.\n\n### References\n\n- [Regular expression Denial of Service - ReDoS (OWASP)](https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS)\n\n### Credits\n\nThanks to [@sondt99](https://github.com/sondt99), who first reported the issue.","aliases":["CVE-2026-48125"],"modified":"2026-06-15T20:41:40.397379Z","published":"2026-06-15T20:15:02Z","database_specific":{"cwe_ids":["CWE-1333","CWE-400"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-06-15T20:15:02Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/faisalman/ua-parser-js/security/advisories/GHSA-9h5v-pfqq-x599"},{"type":"PACKAGE","url":"https://github.com/faisalman/ua-parser-js"}],"affected":[{"package":{"name":"ua-parser-js","ecosystem":"npm","purl":"pkg:npm/ua-parser-js"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.0.1"},{"fixed":"2.0.10"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-9h5v-pfqq-x599/GHSA-9h5v-pfqq-x599.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}