{"id":"CVE-2026-73646","state":"PUBLISHED","title":"PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure","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.","publishedAt":"2026-08-17T15:35:13.518Z","updatedAt":"2026-08-17T16:36:37.422Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["postcss postcss"],"affected":[{"vendor":"postcss","product":"postcss","versions":[{"version":"< 8.5.18","status":"affected"}]}],"references":["https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849","https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c","https://github.com/postcss/postcss/releases/tag/8.5.18"],"weaknesses":["CWE-22"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/73xxx/CVE-2026-73646.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-73646","state":"PUBLISHED","datePublished":"2026-08-17T15:35:13.518Z","dateUpdated":"2026-08-17T16:36:37.422Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-08-13T14:04:09.604Z"},"containers":{"cna":{"title":"PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"postcss","product":"postcss","versions":[{"version":"< 8.5.18","status":"affected"}]}],"references":[{"url":"https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849","name":"https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c","name":"https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c","tags":["x_refsource_MISC"]},{"url":"https://github.com/postcss/postcss/releases/tag/8.5.18","name":"https://github.com/postcss/postcss/releases/tag/8.5.18","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-22","lang":"en","description":"CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-17T15:35:13.518Z"},"source":{"advisory":"GHSA-r28c-9q8g-f849","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-17T16:35:17.036116Z","id":"CVE-2026-73646","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-17T16:36:37.422Z"}}]}}}