{"id":"CVE-2026-73646","aliases":["GHSA-r28c-9q8g-f849"],"url":"https://o3.security/vulnerability/CVE-2026-73646","summary":"PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure","details":"PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.18, lib/previous-map.js loadMap() passes attacker-controlled sourceMappingURL values to join(dirname(opts.from), annotation), and loadFile() permits traversed or absolute .map paths, allowing untrusted CSS processed without map: false to disclose sourcesContent from arbitrary reachable .map files through result.map. This issue is fixed in version 8.5.18.","published":"2026-08-17T15:35:13.518Z","modified":"2026-08-18T03:56:44.655857370Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"postcss","fixedVersion":"8.5.18"}],"fix":{"url":"https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c","label":"postcss/postcss@95663d3"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73646.json"},{"type":"FIX","url":"https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c"},{"type":"WEB","url":"https://github.com/postcss/postcss/releases/tag/8.5.18"},{"type":"ADVISORY","url":"https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73646"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:44.655857370Z"}}