{"cve":"CVE-2026-104844","nvd":{"published":"2026-10-02T16:16:46.917","modified":"2026-10-02T18:44:11.270","status":"Awaiting Analysis","description":"PostCSS Selector Parser is a CSS selector parser that integrates with PostCSS but does not require it. Prior to 7.1.6, src/parser.js splitWord() can receive a flat selector as one word token carrying many class or ID indexes because period and hash characters are not tokenizer word delimiters. The uniqs() deduplication and per-index class and ID membership checks repeatedly scan the class and ID index arrays, while a separate Sass-interpolation filtering pass also performs repeated linear scanning. Together, these passes make parsing quadratic in the number of indexes and allow a crafted selector to occupy a synchronous parser thread. The maxNestingDepth guard does not mitigate the issue because the hostile selector can have zero nesting depth. Only consumers that synchronously parse untrusted selectors in an exposed request path are affected; ordinary build-time parsing of trusted sources is not affected. This issue is fixed in version 7.1.6.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","score":5.9},"cwes":["CWE-400","CWE-407"],"references":["https://github.com/postcss/postcss-selector-parser/commit/62b191792df0a0bc56062e5a875bc74aae2a51cd","https://github.com/postcss/postcss-selector-parser/releases/tag/7.1.6","https://github.com/postcss/postcss-selector-parser/security/advisories/GHSA-rj75-hqrm-r3gf"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:57:46.668721662+00:00"},"epss":{"cve":"CVE-2026-104844","score":0.00389,"percentile":0.32699,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-rj75-hqrm-r3gf","url":"https://osv.dev/vulnerability/GHSA-rj75-hqrm-r3gf","summary":"PostCSS: Quadratic complexity in flat selector parsing allows CPU exhaustion","modified":"2026-10-05T23:00:05.308008424Z","packages":[{"ecosystem":"npm","name":"postcss-selector-parser","purl":"pkg:npm/postcss-selector-parser","ranges":["<7.1.6"],"fixed":["7.1.6"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}