{"cve":"CVE-2026-73646","nvd":{"published":"2026-08-17T16:17:47.257","modified":"2026-09-18T20:05:53.723","status":"Awaiting Analysis","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5},"cwes":["CWE-22"],"references":["https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c","https://github.com/postcss/postcss/releases/tag/8.5.18","https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849","https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:10.689564601+00:00"},"epss":{"cve":"CVE-2026-73646","score":0.0053,"percentile":0.44819,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-r28c-9q8g-f849","url":"https://osv.dev/vulnerability/GHSA-r28c-9q8g-f849","summary":"PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure","modified":"2026-09-10T03:50:52.854537677Z","packages":[{"ecosystem":"npm","name":"postcss","purl":"pkg:npm/postcss","ranges":["<8.5.18"],"fixed":["8.5.18"]}]}],"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."]}