CVE-2026-73646CWE-22path-traversal

CVE-2026-73646

High · published August 17, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
44.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00530 · 44.0th percentile
Weakness
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Published
2026-08-17T20:17Z
References (4)
https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c · [email protected]https://github.com/postcss/postcss/releases/tag/8.5.18 · [email protected]https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849 · [email protected]https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 17 AUG 15:35Z
    PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure
    cvelistv5